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By C. S. Finney, John Mitchell

The growing popularity in the United States of the vertical-flue even was emphasized when in 1905 the United States Steel Corp. chose the Koppers oven as the type which best suited their requirements. Heinrich Koppers was born on November 23. 1872. at a small farm in Walbeck near Geldern on the lower Rhine. When young Koppers was eight years old, however the family moved away from the farm to the industrial city of Bochum in the Ruhr. Here Koppers attended public school and subsequently served an apprenticeship to a tinsmith before taking a job as a lathe operator with a local steel company. He had ambitions to be much more than a machinist, however, and used his week-ends and evenings to improve his theoretical background by taking courses at a vocational-training school in Bochum. After winning the highest honor the school could bestow (the silver Staats-medaille), Koppers went on to continue his education at the Rheinisch-Westfalische Hüttenschule in Duisberg. One of his teachers there, Fritz Wüst who later became a professor at the Technische Hochschule at Aachen, recognizing Koppers' unusual abilities, predicted for him a great future. In 1894 Heinrich Koppers joined the firm of Dr. C. Otto and Co. in Dahlhausen, and in 1899 while superintendent of the Mathias Stinnes mine he built his first battery of ovens for Hugo Stinnes, the German industrialist. Two years later he started his own organization, and in 1902 he made Essen his headquarters. It was to Essen that a group of engineers from the United States Steel Corp. went in 1906 with an invitation to Koppers to design and supervise the construction of four batteries of ovens at the Joliet works of the Illinois Steel Co. Each battery was to consist of 70 ovens. Arriving in the United States in 1907, Koppers established a branch of his firm in Joliet, and construction began. The first battery was fired on July 27, 1908. Rugged and simple, these ovens incorporated basic design features which were to make the Koppers oven and its future modifications the choice of a very large segment of the by-product coking industry of America. The 280 ovens at Joliet were 35 ft long, 8 ¾ ft in height, and tapered from 21 to 17 in. The total daily capacity of the four batteries was 2240 tons of coke. The ovens were of the new cross-regenerative type; that is, instead of longitudinal regenerators serving an entire battery, as in the older Koppers ovens, cross regenerators for each separate oven were employed. Fuel gas was supplied from the side of the battery through ducts in the brickwork known as gun flues, which reached to the center of the battery under the vertical heating-flues. Removable, ceramic gas-nozzles fitted at the top of each gun flue helped to insure good control over the distribution of the fuel gas, and uniform heating conditions were also promoted by regulating the air supply to, and the suction in, each heating flue. A different refractory w& used for each battery. One was built of American silica brick, one of American quartzite, and two of imported German quartzite. The installation at Joliet proved to be very successful, and in 1911, 490 additional' Koppers ovens were built for the Illinois Steel Co. at the great new steelworks at Gary, Ind. By 1912 the H. Koppers Co. had established its headquarters in Chicago and was rapidly extending its business to include construction for such iron and steel companies as the Woodward Iron Co. at Woodward, Ma. (80 ovens in 1912); the Tennessee Coal, Iron and Rail- road Co. at Fairfield, Ala. (280 ovens in 1912); the Inland Steel Co. at Indiana Harbor, Ind. (86 ovens during 1913 and 1914) ; and the Republic Iron and Steel Co. at Youngstown, Ohio (68 ovens in 1913). In 1914 a group of men in Pittsburgh bought a major shareholding in the H. Koppers Co., and moved the headquarters of the organization from Chicago to their own city. Under its new management the company was highly successful in obtaining a large share of the contracts for by-product installations built during World War I. In 1917 the remaining German interests in the company were

Jan 1, 1961

H. Van F. Furman, Denver, Colo. (communication to the Secretary): There are some statements in Dr. Carpenter's interesting paper which appear to require explanation, if not modification.

Jan 1, 1901

By C. H. Ma, J. S. Makris

This paper describes a modified X-ray diffraction microscope wzethod based on the general principles of Berg-Bawett's Method, Lang's Method, and Woosters1 Technique. This new method may be used for stationary or oscillatory photomacrographs, with both reflection and transmission techniques. In the stationary technique, a small point-source of a divergent X-ray beam of white radiation is used; in the oscillatory technique, a monochromatic divergent beam is employed. The chief advantages of the method described herein are that only approximate alignment of the Bragg angle -of-interest is needed during exposure, and that a large portion of a crystal-specimen surface can he irradiated. In recent years, the study of dislocations through X-ray diffraction microscope techniques has received considerable attention as concerns the per,fection of single crystals. Very promising results have appeared in the literature.'-' These techniques are very useful when the dislocation density of a crystal is near 105 per sq cm or lower. The principle of X-ray diffraction microscopy is based on the differential effect of X-ray primary extinction between the distorted parts and the perfect parts of a crystal. When an X-ray beam impinges on a set of planes of a crystal at the correct Bragg angle, diffraction of X-rays will occur with a 90-deg phase shift of the diffracted beam. This once-diffracted beam still forms the correct Bragg angle with the planes ahead of it, if the planes are not distorted. Thus, part of the strength of the once-diffracted beam is rediffracted and the beam continues to travel in the direction of the primary X-ray beam. This twice-diffracted beam not only takes away part of the strength of the once-diffracted beam, but also causes destructive interference with the primary beam because it now is exactly 180 deg out of phase with the primary beam. As the primary beam goes farther and farther into the crystal, its intensity is continuously weakened. Asa result, the ultimate X-ray diffraction power of a set of undistorted planes is largely extinguished. This phenomenon is called primary extinction.1,2'4 If the set of planes ahead of it is distorted, the once-diffracted beam will have less chance to be rediffracted, because it could not meet the exactly correct Bragg angle for rediffraction. If a part of the beam does rediffract, this twice-diffracted beam is not exactly 180 deg out of phase with the primary beam, and thus it causes less destructive interference. As a result, the registered X-ray diffraction power of the distorted part of a crystal appears stronger than that of the perfect part. Thus, point-by-point contrast of a diffraction image is theoretically possible from a crystal containing dislocations. Two most popular X-ray diffraction microscope techniques today are Berg-Barrett's Method and Lang's Method. Both of these techniques require a

Jan 1, 1964

By Meguru Nagamori

DURING the smelting of the sulfide ores of copper, nickel, and certain other metals, a matte phase is formed. For a better understanding of the physico-chemical properties of mattes, binary systems such as Cu-S, Ni-S, Fe-S, and so forth, should be studied, especially in the vicinity of liquid compounds such as Cu2S, Ni3S2, FeS, and so forth. These compounds are relatively stable in the solid state although they can exhibit appreciable deviations from stoichiometry. With small deviations from stoichiometry there are large changes in the activity of both sulfur and metal this is a characteristic of both solid and liquid sul-fides near the stoichiometric compositions. In the vicinityof molten Cu2S,1 for instance, the activity of sulfur increases about 100 times for a 0.012 increase in the mole fraction of sulfur and, correspondingly, the activity of copper decreases greatly. In this sens the minor deviations from stoichiometry should be carefully taken into account in studies of such metal-sulfur melts. Metal-sulfur melts may be considered to have properties intermediate between metallic solutions and molten salts, i.e., neither entirely metallic nor entirely ionic. The radius of the ion sZ- is 1.84 as compared with 1.04? for a single bond covalent s.2 It is therefore inferred that when the sulfur is more ionic its partial molar volume is larger, although metal-metal, metal-sulfur, and sulfur-sulfur interactions may bring about further complexities. Thus, it is to be expected that the molar volumes, which are derived from density-composition relations, will help in resolving the structure of the melts. In this study the maximum bubble pressure method with bubbling gases of H2, H2S, and Ar, .was employed to measure the density. EXPERIMENTAL Materials. Silver of 99.95 pct purity was melted in an alumina crucible and hydrogen gas was then bubbled through the liquid for the deoxidation. In preparation of Cu2S, electrolytic copper powder (>99.9 pct Cu) was mixed with precipitated sulfur and heated to 1200°C in an alumina crucible under a hydrogen atmosphere. Mixtures having the approximate compositions FeS and Ni3S2 were prepared by heating reagent grade electrolytic iron or reduced nickel powder with precipitated sulfur under a hydrogen atmosphere. The H2S gas was of 98.5 pct purity, the impurities being mostly CO2 and CS2 which hardly contaminate the melts. Apparatus. The crucible system is shown schematically in Fig. 1. To minimize the variation of melt composition during a density measurement, the apparatus was designed in such a way that either Ar, H2, H2S, or mixtures of these gases could be used as the bubbling gas. When the melt had a high partial pressure of sulfur, H2S gas was used. When the partial pressure of sulfur was so low that oxygen might dissolve in the melt, the use of H2 was preferred. In intermediate cases, argon or mixtures of H2-H2S were used. Density of Dibutylphtalate. Dibutylphtalate was used as the manometer fluid. Relative to distilled water, the density of the dibutylphtalate, pdib g per cc, was measured and found to be: pdib (25°C) = 1.046 i 0.002. With the use of the temperature coefficient reported by Kemppinen and Gokcen,3 the following value was

Jan 1, 1970

By W. B. Hickman, J. J. Pickell, B. F. Swanson

Many physical properties of the porous media-immiscible liquid system are dependent upon the distribution of fluids within the pores; this in turn, is primarily a function of pore structure, liquid-liquiri interfacial tcnsion and liquid-solid wetting conditions. The cnpillary pressure hysteresis process provides a means of investigating the influence of pore structure upon fluid distribution for consistent sur/acc conditions. Invcstigntiot2s indicate that residual non-wetting-phase saturations /ollozuir,g the imbibition process (i.e.,wetting phase displacing nor2-wctting phase) are dependent upon both pore structure and initial non-raetting phase saturation and suggest that residual fluid is distributed as Discontinuous ,globules, one to a few pore sizes in dimension, thrnugh the entire range 01 pore sizes originally occupied. It clppears that air-mercury capillary pressure dala adequntely rellect the distribution of fluiris in a water-oil system when strong wetting condition preliczil. An oil-air counter-current imbibition technique has also been found to provide a rapid rneans of obtaining residual-initial saturation data. In a majority of cnses, rcsidual saturations detf-rniinecl from the oil-air or air-mercury process reasonably approximate residual oil saturation following water drive of a strongly water-wet medium. INTRODUCTION A reliable estimate of recoverable reserves depends not only on the amount of original oil-in-place but also on pore geometry and distribution of fluids within the pores. A critical parameter determining the recovery from a reservoir under waterflood, for example, is the amount and distribution of residual oil within the various rock types present. The purpose of this paper is to investigate the mechanism of capillary trapping and assess its importance in laboratory measureqents of residual oil saturation. The degree of wettability of a reservoir rock is recognized as an important factor in waterflood or imbibition experiments. In this paper, however, only the water-wet case has been considered. Considerable experimental evidence1 suggests that for water-wet rocks, capillary forces predominate in tile distribution of fluids and that viscous forces in the range normallv of interest in the reservoir have a minimum influence on residual oil saturation. It follows that if the ultimate recovery is controlled by pore geometry, a unique residual non-wetting phase saturation should exist for a given set of initial conditions. Two laboratory procedures.found to be extremely useful in the study of pore structure and degree of fluid interconnection at various saturations are decribed. Although air-nercury capillary injection curves have been used2 previously to characterize the drainage case, the withdrawal or imbibition case can provide valuable supplementary data. The air-mercury process, however, has several disadvantages; it is difficult to run in a sufficiently accurate manner, mercury does not always act as a strongly non-wetting liquid and in the air-mercury process the sample is rendered unsuitable for future analyses. An alternative process is described in which air is the non-wetting phase and naptha, hentane, octane or toluene is the wetting phase. INTERFACIAL TENSION AND CAPILLARY PRESSURE Interfacial tension between immiscible fluids is due to the difference in attraction of like molecules as compared with their attraction to molecules of the neighbouring fluid. This net attraction results in a tension at the interface. To extend the interface; thus, interfacial tension s can also be thought of as free surface energy. Interfacial tension is normally expressed as dynes/cm, and interfacial energy is measured in ergs/cm2 hence, both have dimensions ml A 2 and are numerically equal.

Jan 1, 1967

By M. Bevis, A. G. Crocker

A. G. Crocker and M. Bevis (Battersea College of Technology)— Richman and Richman and conard17 have recently published the very interesting results of their studies on the plastic deformation of Fe-Ni-C martensites and of an Fe-5 wt pct Be alloy. Other work on the range of Fe-Be alloys containing between 16 and 27 at. pct Be has also been reported by Richman." One of the fascinating features of this work is that the materials investigated deform primarily by means of twinning and that several twinning modes are operative in addition to the well-established (112 ) mode of bcc materials The composition planes of these unusual twins were determined using a single-surface analysis and reported as (0131, "{045)" or "{089)", and It is now thought1' that the "{0,1,13)" habit reported for the Fe-Ni-C alloys'' is more likely to be near "{127)". Although the full twinning elements of these unusual twinning modes could not be determined directly from the experimental results, the authors attempt to deduce the elements by considering twin intersectionslQ and by using the projection technique of Jaswon and Dove. The basic assumption of their approach is that the (013) habits are truly rational planes but that the other habits are irrational and merely approximated to by the indices quoted above. They thus deduce that the twinning mode describing the (013) habit is either Type I or compound and that the modes describing the other habits are Type 11. This deduction must however be false as all twinning modes in cubic structures obeying the classical orientation relationships of deformation twinning must be compound. Type-I and Type-I1 modes can occur in all of the other crystal systems (indeed in the triclinic system compound modes are not allowed), but in the cubic system only compound modes can arise. This fact, which does not appear to be well-known, fol- lows immediately from the relations between the four twinning elements defining a twinning mode. Thus for a Type-I mode which is uniquely defined by the rational twinning elements K1 = hi and given by: where the summation convention of the tensor calculus has been adopted. For cubic materials the metrics and reduce to the unit tensors and j so that we have It is clear from these equations that both ki and ui must take on integral values; i.e., Kz, and ql must be rational, if hi and vi are integers, i.e., if K1 and are rational. Thus for cubic materials a Type-I mode must degenerate into a compound mode and the same result also arises for Type-II modes. The apparently irrational habits observed by the authors can thus not be explained in terms of Type-I1 twinning if the classical laws of deformation twinning are to be obeyed. An alternative explanation of the irrational habits is that they may arise from twinning modes with four irrational twinning elements. These modes, which do not obey the classical orientation relationships associated with deformation twinning, have been shown to arise as the result of double twinning processes in magnesium,22 but may also describe a simple shear on an irrational plane in an irrational direction. Indeed double twinning processes in bcc

Jan 1, 1963

By Nick Holonyak

Halogen vapor-transport synthesis of Ga(As,-,Px) and its preparation into laser junctions are described. Electrical and optical properties of Ga(As,-,PX) laser junctions are discussed. The present limitations in these properties are related to material proble?vzs and the very early state of development of Ga(As,-,PX), and are discussed in this context. Inhonzogeneity problems, fluctuation of As :P ratio, and problems with deep-level contaminants are described and related to Ga(As,-,PX) junction performance. Laser junctions are demonstrated which operate to wavelengths as short as 6470 A (77°K). The prospect that Ga(As,-,P,) will operate to wavelengths perhaps 100A shorter is mentioned. IN this paper we wish to describe some of the more important features of almost 1 year of experience in the preparation and properties of Ga(As,-,P,) p-n junction lasers. Because much data so far available are far from complete, some of the results still must be considered tentative and subject to correction and revision as work on Ga(As,-,P,) crystal problems progresses. Although the electrical, optical, and device properties of Ga(As,-,P,) junction lasers are understandably of considerable interest, the work to date points out that by far the most serious problems extant and those deserving first attention are problems involving the growth, doping, and perfection of Ga(As,-,P,) crystals. One of the most formidable of these is to grow Ga(As,-,P,) sufficiently free of deep levels, either due to contaminants or to structural imperfections, to allow fabrication of laser p-n junctions which can be cooled and not suffer from "freeze-out" of carriers on deep levels (and consequent double-injection behavior). In addition to the problems of growing crystals adequately free of deep levels and generally of the highest perfection, so that the best possible laser junctions can be realized, the further goal remains of increasing the phosphorus content well beyond 40 pct in an attempt to determine the practical lower wavelength limits of laser action in the Ga(As,-,P,) system. Even though the laser junctions prepared in Ga(As,-,P,) are of importance in their own right, we have considered them at this point mainly a means to study the growth and crystal problems of the material. It can be concluded that the laser junctions now available are almost completely limited by the purity and structural deficiencies of Ga(As,-,P,) crystals, and cannot be fairly compared with, for example, GaAs p-n junction lasers until Ga(As,-,P,) crystal growth has been more extensively developed. The basis for the statements above will become evident in the following sections which describe Ga(As,-,P,) crystal and junction preparation, and laser-junction properties. G(As,-,P,) CRYSTAL GROWTH As previously reported,2 we have found it convenient to employ the halogen vapor-transport process3 for synthesizing Ga(As,-,P,) crystals for use in laser junctions. Commercially available GaAs and Gap, separately prepared by halogen vapor tranport, are sealed in the desired ratio in a quartz vessel with a quantity of column-VI donor and a small quantity of metal halide which supplies the halogen for transport. The sealed ampoule, as shown in Fig. 1, is heated at a temperature in the range from 1025" to 1100°C at the position of the source GaAs and Gap. The GaAs and Gap are simultaneously vapor-transported and deposited as Ga(As,-,P,) at one end of the ampoule

Jan 1, 1964

By M. Bevis, A. G. Crocker

A. G. Crocker and M. Bevis (Battersea College of Technology)— Richman and Richman and conard17 have recently published the very interesting results of their studies on the plastic deformation of Fe-Ni-C martensites and of an Fe-5 wt pct Be alloy. Other work on the range of Fe-Be alloys containing between 16 and 27 at. pct Be has also been reported by Richman." One of the fascinating features of this work is that the materials investigated deform primarily by means of twinning and that several twinning modes are operative in addition to the well-established (112 ) mode of bcc materials The composition planes of these unusual twins were determined using a single-surface analysis and reported as (0131, "{045)" or "{089)", and "{2,3,10)" or "(127)". (It is now thought1' that the "{0,1,13)" habit reported for the Fe-Ni-C alloys'' is more likely to be near "{127)". Although the full twinning elements of these unusual twinning modes could not be determined directly from the experimental results, the authors attempt to deduce the elements by considering twin intersectionslQ and by using the projection technique of Jaswon and Dove.' The basic assumption of their approach is that the (013) habits are truly rational planes but that the other habits are irrational and merely approximated to by the indices quoted above. They thus deduce that the twinning mode describing the (013) habit is either Type I or compound and that the modes describing the other habits are Type 11. This deduction must however be false as all twinning modes in cubic structures obeying the classical orientation relationships of deformation twinning must be compound. Type-I and Type-I1 modes can occur in all of the other crystal systems (indeed in the triclinic system compound modes are not allowed), but in the cubic system only compound modes can arise. This fact, which does not appear to be well-known, fol- lows immediately from the relations between the four twinning elements defining a twinning mode. Thus for a Type-I mode which is uniquely defined by the rational twinning elements K1 = hi and tj2 = vi (i = 1, 2, 3), the Kz qd 771 elements are given by: where the summation convention of the tensor calculus has been adopted. For cubic materials the metrics cij Iand cij reduce to the unit tensors 6ij and 6ij so that we have It is clear from these equations that both ki and ui must take on integral values; i.e., Kz, and ql must be rational, if hi and vi are integers, i.e., if K1 and 77~ are rational. Thus for cubic materials a Type-I mode must degenerate into a compound mode and the same result also arises for Type-II modes. The apparently irrational habits observed by the authors can thus not be explained in terms of Type-I1 twinning if the classical laws of deformation twinning are to be obeyed. An alternative explanation of the irrational habits is that they may arise from twinning modes with four irrational twinning elements. These modes, which do not obey the classical orientation relationships associated with deformation twinning, have been shown to arise as the result of double twinning processes in magnesium,22 but may also describe a simple shear on an irrational plane in an irrational direction. Indeed double twinning processes in bcc

Jan 1, 1963

By J. A. Snyder, W. L. Finlay

G. Edmunds—Solid solubility is considered to be of either the interstitial or the substitutional type. Is it possible, in a binary alloy as the simplest case, that some of the solute atoms are present in the normal lattice sites (substitutionally or filling lattice vacancies) while simultaneously others are in interstitial positionss One might even ask whether a distribution of the two types may be the normal situation. H. M. Meyer—Metastable states of interstitial atoms occupying vacant lattice sites possibly occur as well as of substitutional atoms squeezed in between regular matrix positions. However (as we know since Hume-Rothery), the solute atoms choose between the two kinds of solutions; consequently, every solute will be unequivocally either substitutional or interstitial in the equilibrium state of the solid solution. M. Balicki—In view of the fact that the authors apparently correlate the analysis of the alloys at the ingot stage with the properties exhibited at the testing stage, I would like to ask whether this is a fully justifiable procedure. In other words, how good are their determinations of solute concentration for correlating them with the mechanical properties. The answer to this question may explain some of the divergencies. Assuming good enough homogenization of the samples and exact determination of mechanical properties the position of the plotted experimental points will depend solely upon the accuracy of composition determination. If this is not accurate, say due to loss or pickup of elements during processing from the ingot to the testing stage, or due to a systematic error in the method employed for obtaining solute concentration data, the points will deviate from their true position and may align themselves along a different curve than the one expected. H. V. Kinsey—We have been studying the creep-rupture properties of titanium-base alloys at 1000°F. In the course of this work, anomalies in behavior of the alloys that would suggest that the material under test was becoming stronger as the test progressed have been observed. If this was so, the most likely explanation that we could think of was that the test bars were absorbing oxygen and nitrogen from the air during the test and were thereby becoming strengthened. In an attempt to determine the strengthening effect of absorbed oxygen and nitrogen the following experiment was conducted. A length of cold-rolled titanium was supplied by the E. I. du Pont Co. Two test bars, having a 1/4 in. diam gauge length, were prepared from this material. One bar was tested in the as-received condition. The second bar was heated in air at 1550°F for 100 hr and subsequently air cooled prior to testing. A testing temperature of 1000°F was employed. The results of these tests are tabulated in table 11. In the author's opinion, is it reasonable to assume that the bar that was exposed to air at 1550°F for 100 hr was stronger because it absorbed oxygen and nitrogen from the air during this heat treatment? W. L. Finlay (authors' reply)—Direct experimental evidence for or against Mr. Edmunds' interesting suggestion will probably never be available. It seems possible, however, that mixed interstitial-substitutional solid solution might well occur with interstitial elements. The less likely possibility of interstitial solution of a normally substitutional element like copper in aluminum was recently discussed at length by the

Jan 1, 1951

By C. W. Phillips, D. N. Frey

A commercial Ti-Fe-Cr alloy, Ti-150, exhibits a martensitic transformation on cooling and two nucleation and growth reactions, one above and one below the Mg-Mf region, on isothermal holding below the single-phase ß temperature range. The reactions were followed by metallographic, X-ray diffraction, and microhardness methods. THE rapidly expanding engineering application of titanium and its alloys makes increasingly urgent an adequate knowledge of the effect of heat treatment on this material. The work herein reported is an attempt to determine certain aspects of the behavior of a commercially available alloy, Ti-150, during heat treatment. The alloy, with a nominal composition of 2.7 pct Cr, 1.3 pct Fe, 0.25 pct 0, 0.02 pct N, and 0.02 pct C, was received in the as-rolled condition as a 3/4 in. round. Slugs 0.11 to 0.12 in. thick were cut under a coolant using a silicon carbide wheel. Preliminary work established that the alloy consists of two phases, a (hexagonal close-packed) and /3 (body-centered cubic), at temperatures below 1750" to 1775"F, and of only /3 phase at higher temperatures. The slugs were heated for 1 hr in air at 1800°F to form a single-phase /3 matrix, then transferred to molten tin (1250° to 1650°F) or lead (1150°F and below) for isothermal holding. Holding temperatures ranged from 700° to 1650°F, times from 0.001 to 23 hr. The treated slugs were then sectioned, one part for metallographic examination and diamond pyramid hardness, the other, after deep etching to remove the high oxygen surface,' for comparative lattice parameter determination and X-ray phase identification. Hardness measurements were taken on the lightly etched surfaces of the metallographic specimens; a 1000 g load on a 136° diamond pyramid was used. Five impressions on each sample were made and the average of the hardness calculated. The use of microhardness measurements to follow the course of an isothermal transformation reaction is undesirable because of the possibility of wide differences in microconstituent hardness.' They were used in this case, however, because of the small amount of material available. At the higher transformation temperatures, where the above-mentioned objection was apparent, the readings were proportioned to correspond to the estimated ratio of transformed and untransformed constituents present. At lower temperatures, resulting in much finer microconstituents, the microhardness measurements were more uniform. The standard deviation of the mean of five impressions calculated from these latter values was 4.2 DPH. Employing 2a limits (probability 0.95) the experimental error of the hardness measurements averages was 8.4 DPH. The etchant used was composed of one part glyc-erol and one part 48 pct hydrofluoric acid." Of a number of etches tried, this one appeared most satisfactory. All micrographs were taken at 500X magnification and with oblique lighting to permit easier identification of the acicular structure resulting from rapid cooling. No advantage was gained by using polarized light for metallographic examination. Phase identification and lattice parameter measurements were made with a North American Philips high angle spectrometer in conjunction with a recording potentiometer. Considerable difficulty was encountered with some of the lattice parameter measurements because of the extreme broadness of the few diffraction lines obtained from samples consisting mainly of strained, untempered, quenched structures.

Jan 1, 1953

By L. H. Sjodahl, J. B. Conway

of each particle on grain boundary movement is proportional to the area it occupies on the grain boundary and this increases with the square of the particle radius. In contrast to the impression gained by Tiwari the effectiveness of a particle, as a grain boundary obstacle, increases rapidly as the particle size increases. The counterbalancing factor in a dispersion of constant volume (e.g., those considered by Zener) is of course the rapidly diminishing number of particles, a situation which does not exist in thoria dispersed materials where the volume fraction of thoria remains constant. Although it has been assumed that the Zener approach is valid for the sake of the above argument, it is open to the following objections: 1) It assumes that the effect of many small particles along a grain boundary is cumulative and does not take into account the possibility of each small particle being overcome separately. In this case the boundary will not be able to move forward until the largest particle on the boundary has been overcome. This means that the rate controlling factor will be the rate at which a few relatively large particles are overcome with the remaining small particles playing a negligible role. 2) When the dispersion consists of very small particles the interparticle spacing is usually small compared to the grain size and most particles are located away from grain boundaries where they can play no part. The most efficient dispersion, from a purely geometrical viewpoint, is one where the particle spacing is equal to the grain size so that all the particles are on grain boundaries. Tiwari's second point that voids cannot prevent re-crystallization seems to be unfounded as several workes20-23 have shown that voids alone can retard grain boundary movement and recrystallization. To further convince Tiwari, Fig. 17 shows a void in deformed TD Nichrome holding back a recrystallization interface. Tiwari's explanation for the effect of voids on recrystallization, i.e., they reduce local strain energy and hence lower the driving force for recrystallization may be valid in itself but is irrelevant to the present case where even complete recrystallization after ONE of the more recently proposed expressions for describing stress-strain behavior is that due to Voce.1,2 This equation is usually written: s =s8 ?(s8?so)e??/?c [l] where s is the true stress, ? is true strain, cC is a constant called the characteristic strain, s8 is the asymptotic stress approached at high strain values, and so is the threshold stress at which the plastic deformation begins. While this expression has not been universally accepted as yet it does contain certain features which are consistent with experimental stress-strain behavior. In a more recent publication Hsu, Davies, and Royles3 employed the concept of generalized strain proposed by seth4 and identified a method for linearizing the stress-strain plot. In this approach the generalized strain was given by: where 7 is the generalized strain, 1 is the instantaneous length, 1, the datum length, and n is a constant called the "coefficient of strain measure". A value of n was said to exist which would yield the linearity: s —s+ S[.-(tf] [3] In recent studies of both these approaches, it has been found that while the Voce equation and the gen-

Jan 1, 1970

By S. C. Schaeker, A. W. Schlechten, A. H. Larson

PARRAVANO and Malquori' studied the equilibrium of H2S-Hz with molybdenum and its lowest sulfide which they believed to be MoS2. Mc Cabe' has shown that its composition is actually Mo2S3 and determined its dissociation pressure by means of Knud-sen effusion measurements. Stubbles and Richard- son3 have recently studied the equilibrium of gas mixtures of H2S-HZ with the two-phase solid mixtures of Mo-MozS3 and Mo2S3-MoS2. The latter investigators found that M02s3 deviated slightly from the stoichiometric composition, but they did not determine the homogeneous region of the disulfide phase. Morimoto and Kullerud, studied the Mo-S system by quenching, microscope, and X-ray methods and concluded that the disulfide is stoichiometric. The present investigation was concerned with the measurement of the sulfur vapor pressure variation with composition at 1100°C in the homogeneous region of "MoS2". These measurements were made by reacting: 1) molybdenum powder (99.97 pct Moj with sulfur vapor, and 2) MoS1.g9 (formed by reaction of Mo + H2S) with sulfur vapor in a quartz capsule. Conditions were controlled to form an equilibrated phase within the homogeneous region of the disulfide. The quartz capsule was sealed off initially under a vacuum and the residual gases were gettered by titanium powder contained in one end of the capsule. A mixture of Mo + S or MOS,., + S was in the other end. The section containing the titanium powder was heated for 24 hr at 700°C and then removed by flame sealing. The end of the capsule containing the charge was then heated to 1100°C. The other end of the capsule was maintained at a temperature which would produce the desired sulfur pressure in the capsule (liquid sulfur distilled from the charge mixture was retained in this end). After equilibration, the capsule was removed from the heating assembly and rapidly air-cooled. It is assumed that equality existed between the total sulfur pressures (PT) in the two ends of the capsule and not between the partial pressures of the different molecular species (S, SZ, Three separately controlled heating elements were used to maintain the proper temperature gradient over the length (approximately 12 in.) of the capsule. A thermocouple-Wheelco "Capacitrol" system was used for temperature control of the two end heating elements within 2"C. The center heating element was controlled directly by a " Power -stat". Separate controlling and measuring thermocouples were used for both end heating elements. Pt-Pt(l0 pct Rh) thermocouples were used for 1100°C and Chromel-Alumel thermocouples were used for lower-temperature control and measurement of the assembly. Silver foil was wrapped around the end of the capsule containing the liquid sulfur to insure a constant temperature zone. The thermal gradient over the entire length of the capsule was measured to: 1) ascertain that the length of the constant temperature zone of the liquid-sulfur end and the sulfide end was sufficient, and 2) ascertain that the liquid-sulfur zone was the zone of lowest temperature. The data obtained in this investigation are shown in Fig. 1 and Table I. The total sulfur pressure (PT) and p(S2) were calculated from the data of Braune et UZ.~ The compositions of the equilibrated disul-

Jan 1, 1964

By E. M. Cox, A. S. Skapski, N. H. Nachtrieb, M. C. Bachelder

D. T. ROGERS*—The conclusions drawn in this paper have important practical significance to the steelmaker and the metallurgist if, in practice, it is demonstrated that metallic copper in the charge will pick up sulphur from the furnace atmosphere and thus increase the sulphur content of the bath. The problem of residual copper arising out of increasing copper in the scrap available to the industry is, in itself, a matter of concern to the steel maker. If, in addition to the often detrimental effects of high residual copper upon the physical properties of some important steel grades, there is to be a complication of the sulphur problem, then we have a set of conditions that bodes no good for the open hearth melter and the open hearth metallurgist. M. B. BEVER*— Investigations of gas-metal equilibria continue to be of interest, especially as new possibilities for improving experimental techniques emerge. Higher purity of reacting substances, better refractories, improved methods of temperature control and an increased awareness of the pitfalls of high-temperature equilibrium work are

Jan 1, 1950

By ELLSIVOKTH DAGGETT

THE Berlin gold quartz mine is situated in Nye county, Nevada, on the west flank of the Shoshone range, about 40 miles south and 30 miles west from the town of Austin, the county-seat of Lander county. The distance from Austin is about 60 miles by stage-road. The outcrop of the vein, at the top of the incline-shaft, is situated just at the base of the mountain proper, almost exactly at the intersection of the mountain-side with the gravelly bench that slopes for about three-quarters of a mile to the flatter sage-brush plain, or desert valley, below. The -vein itself consists almost entirely of quartz, with perhaps 2 per cent. of sulphide of iron, copper, lead, zinc and antimony, and perhaps a trace of some of the compounds of tellurium with gold and silver, although none of the latter have been as yet positively identified. The relative proportion, by weight, of silver and gold in the ores, varies in different parts of the vein, from 12 silver for 1 of gold, to 7 silver for 1 of gold. The quartz vein-filling is usually frozen fast to the walls, and is very hard and compact, seldom showing the friable, fissured, or shelly structure often to be found in quartz veins. Comparatively little evidence of relative motion of one wall of the vein upon the other is to be found-a fact indicating that during the formation of the vein, and prior to the extensive movements herein described, little disturbance had taken place. No evidence whatever of metasomatic origin has been observed. On the other hand, occasional occurrences of comby structure, in which the axes of the quartz crystals are at right angles to the plane of the vein, rather indicate deposition from solution in a pre-existing fissure. Spurs, or branches, and small parallel veins, while not en-\

Mar 1, 1907

By J. C. Karcher

GEOPHYSICAL methods have been more extensively applied to prospecting for oil during 1936 than at any previous time. Their use has been extended to include al- most every oil and gas producing area in the United States. More than ten magnetometer parties, more than nine gravimeter parties, more than five electrical surveying crews, more than fifty torsion balance parties, more than two hundred seismic reflection parties, and several refraction parties were- operating in the United States throughout the year. A tendency has been noted to abandon the use of the pendulum for geophysical prospecting in the oil fields and to increase the use of the

Jan 1, 1937

President MRS. HARRISON SOUDER Smith Paramus Road Ridgewood, N. J. First Vice-president MRS. ROBERT HURSH 10 Kilburn Road Belmont, Mass. Second Vice-president MRS. ERLING L. JORGENSEN 95 Knollwood Rd. Short Hills, N. .1. Third Vice-president MRS. PERCY E. BARBOUR 1R(; Riverside Drive New York, N. Y. Fourth Vice-president MRS. C. B. MURRAY 2040 Stearns Rd. Cleveland, Ohio

Jan 1, 1938

By A. H. Daane, W. J. Wunderlin, B. J. Beaudry

The solid solubility of holmium in copper, silver, and gold, determined using metallographic techniques, was found to be a maximum of 0.06, 2.4, and 3.2 wt pct, respectively, nt the eutectic temperatures. The temperatures of these eutectic horizontals, determined by differential thermal analysis, were found to be 868", 787", and 778"C, respectively. The first compound on the silver-rich side of the Ag-Ho system was found to be A&Ho2. In a study by Gold et al.,' on the effect of small amounts of soluble impurities on the electrical resistance and thermoelectrical properties of copper, traces of iron were shown to have drastic effects on the thermoelectric power due to the magnetic scattering of the conduction electrons. Since little is known about the state of the iron ion when dissolved in copper, Gold had hoped to repeat these experiments using certain rare earths as the magnetic scattering centers; because of the tightly bound 4f electrons it is not expected that their spectroscopic state would be affected by alloying. In such an experiment the sole role of the trace rare-earth impurity would be to magnetically scatter the copper conduction electrons without producing appreciable distortions in the otherwise pure copper matrix. Since holmium was chosen for such a study because of its high magnetic moment, it was necessary to establish precisely its solid solubility in copper. The study was extended to include the solvents silver and gold, so that an evaluation of the data using classical solubility parameters could be made. No previously reported work on the systems of holmium with copper, silver, or gold was found in the literature. Information on the solubility of other rare earths in these three metals is also very meager. The solubility limit of yttrium in copper was reported as less than 1 wt pct2 and the solubility of praseodymium in gold as 0.35 wt pct,3 while no references were found on solubility studies of rare earths in silver. EXPERIMENTAL Materials. The materials used in this investigation were distilled holmium prepared in this Laboratory, OFHC* copper, electrorefined silver (99.9 *OFHC = oxygen-free high conductivity. pct), and gold with the analyses given in Table I. Sample Preparation. Samples weighing 1 to 2 g were prepared by arc-melting the components together on a water-cooled copper plate under purified argon atmosphere. The samples, turned and remelted at least five times to ensure homogeneity, showed weight changes of less than 0.1 wt pct after melting. Samples containing less than 0.7 wt pct Ho were prepared by diluting 1 to 2 wt pct Ho alloys with the pure solvent, while samples with concentrations greater than 0.7 wt pct Ho were prepared directly from the metals. The samples were wrapped in tantalum foil, sealed in outgassed Vycor tubing under helium, annealed at the desired temperature for at least 24 hr, and then quenched by shattering the Vycor tube in cold water. Metallographic Methods. Standard mechanical polishing methods were used in preparing the silver and gold alloys for examination, while the copper alloys were electropolished using a 40 pct solution

Jan 1, 1963

By Thomas L. Wright

Exploration activities were maintained at a high level throughout 1966. Numerous significant discoveries and developments in which geologists played an important part were announced. Although the complete results of exploration activities carried out during the year by private companies have not been announced, the following are among the more important developments that have been made public knowledge. In the western states, exploration for practically all of the metals continued at a high rate. Substantially increased interest in uranium occurred this year, and it is felt by many that a real boom in the demand for uranium may come about in the near future. The reasons have been the more rapid acceptance of atomic power than had been anticipated, and that uranium producers can now sell their product to private interests and even foreign countries. A tremendous demand for uranium is anticipated by many, and this has rekindled exploration activity. On the Colorado Plateau, in Wyoming, and in the area around Grants, N. M., a number of companies have undertaken uranium exploration programs, among which are Kerr-McGee, Homestake, Anaconda and Utah Construction. A new uranium orebody in Texas was brought into production early in 1966 by Susquehanna Western.

Jan 2, 1967

By Stuart H. Ingram

The term lightweight aggregate implies material which may be substituted for the usual rock, sand and gravel commonly used as the major part of concrete, but distinguished by being much lighter in weight. Background The art of making and using concrete is old and well developed. Research and experience have pretty well determined the qualities necessary in its constituents, and time has tested theories and applications. Elaborate specifications and tests have been devised and generally adopted governing all phases of concrete work, from selection of material, through engineering design and down to mixing and placing. Standard practices have become routine to executives and laborers, and operations have been simplified and costs lowered. Though many lightweight aggregates meet the basic specifications necessary for usefulness, their physical qualities are so different that they fiequently will not pass standard tests, and some of them cannot be mixed and placed with the usual formulas for water and slump. As a rule their use produces a concrete with a lower modulus of elasticity which requires design change, and being produced in much smaller quantities than ordinary aggregate, production costs are higher. This latter works in a vicious circle to restrict their use and maintain prices that are not competitive, except as against each other. Increased Demand In spite of such handicaps consumption has grown steadily for the past two decades and is apparently growing even faster today. It is evident that lightweight concrete must have better qualities, and be sufficiently better to Overcome the higher cost and the other difficulties and disadvantages pertinent to the use of a new and different material in an old industry. Hence the study of its main ingredient should be of interest to all engineers. Our group has a double interest in the subject since most of the materials which have been used as sources of lightweight aggregate are either mined, Or are by-products of mining operations. We are directly interested in their production as well as their use, and since available supplies of materials suitable are limited, the increasing use, and rising demand, make the discovery of new Or or the development of processes to adapt other natural materials to this use, a promising field; and one in which our profession should take an active part. Recent Development Descriptions of ancient work contain references to the use of spalls of tuffs Or pumice in concrete masonry, but it is only since the nineteen twenties that serious attempts have been made to produce and market lightweight aggregates. A period of rapid advance in theory and practice in cements, mortars and con-

Jan 1, 1948

By Stuart H. Ingram

The term lightweight aggregate implies material which may be substituted for the usual rock, sand and gravel commonly used as the major part of concrete, but distinguished by being much lighter in weight. Background The art of making and using concrete is old and well developed. Research and experience have pretty well determined the qualities necessary in its constituents, and time has tested theories and applications. Elaborate specifications and tests have been devised and generally adopted governing all phases of concrete work, from selection of material, through engineering design and down to mixing and placing. Standard practices have become routine to executives and laborers, and operations have been simplified and costs lowered. Though many lightweight aggregates meet the basic specifications necessary for usefulness, their physical qualities are so different that they fiequently will not pass standard tests, and some of them cannot be mixed and placed with the usual formulas for water and slump. As a rule their use produces a concrete with a lower modulus of elasticity which requires design change, and being produced in much smaller quantities than ordinary aggregate, production costs are higher. This latter works in a vicious circle to restrict their use and maintain prices that are not competitive, except as against each other. Increased Demand In spite of such handicaps consumption has grown steadily for the past two decades and is apparently growing even faster today. It is evident that lightweight concrete must have better qualities, and be sufficiently better to Overcome the higher cost and the other difficulties and disadvantages pertinent to the use of a new and different material in an old industry. Hence the study of its main ingredient should be of interest to all engineers. Our group has a double interest in the subject since most of the materials which have been used as sources of lightweight aggregate are either mined, Or are by-products of mining operations. We are directly interested in their production as well as their use, and since available supplies of materials suitable are limited, the increasing use, and rising demand, make the discovery of new Or or the development of processes to adapt other natural materials to this use, a promising field; and one in which our profession should take an active part. Recent Development Descriptions of ancient work contain references to the use of spalls of tuffs Or pumice in concrete masonry, but it is only since the nineteen twenties that serious attempts have been made to produce and market lightweight aggregates. A period of rapid advance in theory and practice in cements, mortars and con-

Jan 1, 1948