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By B. J. Reid, J. N. Greenwood

It has been shown1 that cavities are formed in the grain-boundaries of copper and 70:30 brass (as well as in magnesium) by the application of tensile stresses at elevated temperatures. For a given rate of strain, cavities are formed in brass at a lower temperature than in copper, and they are larger; it was thought that this earlier onset of cavitation in the alloy might be caused by the distortion produced in the metal lattice by the alloying element. If the cavitation is caused by the vacancy-migration mechanism, ' the distortion of the lattice would reduce the energy required for vacancy formation, and thus provide vacancies more readily to assist in the cavitation process. It was decided to study a range of alloys to find out whether increasing amounts of an alloying element would cause any progressive increase in, or modification of, the cavitation in copper. Nickel was chosen for this purpose, since it is soluble in copper throughout the whole range of alloys. A further advantage was its low vapor pressure, which enabled the preparation of the alloys in vacuum and the consequent reduction of their hydrogen content. It has been suggested that cavities may be nucleated by the migration of hydrogen atoms to the less regular atomic spacing at the boundary, and their combination to form molecules. The latter being too large to diffuse back into the lattice, form stable cavities into which vacancies could condense. PREPARATION OF ALLOYS All alloys, ranging from pure OFHC copper to 43.7 at. pct of nickel (carbonyl), were prepared in a vacuum furnace employing high-frequency induction heating. When a charge was melted, vigorous gas evolution occurred initially, after which the pressure was reduced to 10-4 mm Hg, using an oil-diffusion pump. After remaining molten for a further 1/2 to 1 hr to aid degassing, the melt was allowed to solidify in the crucible. In this way contamination by gases evolved from the surface of a separate mold was avoided. The list of alloys prepared is shown in Table I. The percentage of hydrogen present in the OFHC copper was reduced from 0.0054 at. pct to 0.0012 at. pct, as measured by a vacuum-fusion method. The alloys were cold-rolled to 0.03-in.-thick strip, and were homogenized in vacuum for 1 hr at 900°C after every 30 pct reduction. At a thickness of 0.05 in., the strip was held at 450°C for 24 hr under high vacuum (10-5 mm Hg) in an attempt to reduce the hydrogen content still further. Tensile specimens were prepared with a gage length of 1 in., and were finally annealed for 2 hr at 800°C to give an average grain diameter of 0.1 mm. TENSILE DEFORMATION The specimens were deformed in a tensile straining machine operated by a synchronous motor at a constant rate, equivalent to 1.7 pct per hr on a 1-in. gage length. The specimen and grips were contained in a vacuum jacket. A pressure of 10-2 mm Hg was maintained, which was sufficient to prevent surface tarnishing of a specimen held at 650°C for 24 hr. Tests were made between 20. and 650°C and the temperature was controlled to within ±3° over the gage length. The load was measured by the deflection of a cantilever spring. a) Mechanical Properties-The ductility curves shown in Fig. 1 fall into two groups. Figs. 1(a) and (b) for copper and the 5 pct nickel alloy, respectively, show a continuous fall in ductility with a steep fall between 200° and 400°C. Figs. l(c) to (f) show the same sudden loss of ductility between 200° and 400°C. With higher temperatures, however, there is a recovery in ductility values to a maxi-

Jan 1, 1959

By S. R. Maloof, W. R. Mitchell, J. A. Mullendore

Preliminary experimental evidence is presented to show that the metallic impurities aluminum, iron, and silicon, and beryllium oxide as found in commercially pure hot-pressed beryllium powder can be reduced to lower Concentrations by Zone -Purification techniques. The reduction in the concentration of aluminum to extremely low levels (10 PPm) is noteworthy, since earlier work demonstrated that aluminum is a major factor contributing to the hot-tearing of beryllium during fusion welding. On the basis of present findings, a method is suggested for producing beryllium metal of improved weldability. EXPERIMENTAL research now being conducted on the purification of beryllium indicates that several of the metallic impurities and beryllium oxide can be reduced to lower concentrations by employing standard horizontal zone-refining techniques. For the preliminary work, commercially-pure hot-pressed beryllium having a purity of 97.84 pct was used. The chemical composition is given in Table I. The hot-pressed beryllium was machined into bars 5/8 by 5/8 by 4 to 6 in. in length. Beryllium-oxide boats which had been conditioned by prior heating in a vacuum of 10"5 mm of Hg at 1100°C for 3 hr were used to hold the beryllium while it was zone melted. The boat with its charge, along with a smaller beryllium-oxide boat containing scrap beryllium to be used for gettering purposes, was loaded into a quartz tube and evacuated to 10-6 mm of Hg. Alter alternately evacuating and flushing three times with purified argon, the furnace tube was backfilled to a pressure of 1/6 atm of A and sealed off by means of a vacuum-tight stopcock. It was then removed from the pumping equipment and mounted on the traveling carriage of the zone-refining apparatus. Heating was accomplished with a 10 kw 450 kc induc- tion heating unit using an induction coil consisting of two turns of 3/16-in. diam copper tubing. Before starting to zone melt, the atmosphere in the furnace tube was gettered by heating the scrap beryllium in the smaller boat to above its melting point and holding at temperature for several minutes. The carriage was then shifted so as to locate one end of the beryllium ingot in the large boat within the induction coil. A molten zone approximately 3/4 to 1 in. was established by loading directly into the ingot. The molten zone was moved very slowly along the length of the ingot. Before each pass was made the procedure for evacuating, flushing, and backfilling, and so forth was repeatedI' Speeds of 1 1/2 and 3 in- per hr were used with up to twelve zone passes. The appearance of a typical zone-refined ingot is shown in Fig. 1. After zone refining, the grains in the ingot appear to be elongated in the direction of zone travel, whilst before, they are essentially equi-axed. A microexamination revealed the presence of a network in the beryllium grains as seen in Fig. 2. Laue spots in back reflection pictures taken of the sample were not sharp, indicating the presence of subgrains in the structure. As can be seen, however, many of the network boundaries cross beryllium grain boundaries. It has been shown by Martin and Moore1 that beryllium solidifies as a bcc structure which then transforms to the hexagonal structure at about 1250oC.It is believed that the observed network is merely the outline of the bcc structure which formed from the melt and are not subgrain boundaries. In order to eliminate surface contaminants, approximately 1/16 of an inch of material was removed from the outer skin of each ingot after zone refining.

Jan 1, 1962

By F. B. Plummer

THE physical properties of oil-producing sands, such as grain size, porosity, and permeability, are becoming more and more important in petroleum production engineering as oil fields are being repressured and rejuvenated. A number of excellent papers have been published recently on all three of these properties. Faucher, Lewis and Barnes1 give a com-plete survey of the work done through 1932 and contribute also much information on sands that they themselves have examined. Muskat and Botset,2 Wykoff, Botset, Muskat and Reed,3 Hurst,4 and Muskat5 have contributed a great deal to the theory and actual measurement of flow of liquids and gases through porous media. Muskat and Botset have measured the permeabilities of different sands with gases and liquids. They find that the radial is always slightly under the linear permeability. However, in most of the previous experiments small samples of the sand were used, and the method of production of fluid or gas through the sands has not been very close to actual oil-field conditions. In addition, so far as the authors are aware, no measurements of linear and radial permeabilities have been made simultaneously under exactly the same conditions. The multiple permeability apparatus described here is a part of the equipment being acquired by this laboratory for thorough investigation of the physical properties of producing sands. It possesses certain advantages for comparative studies of liquid flow. Additional data and descriptions of other instruments will follow in papers to be written later on. The essential features of the permeability apparatus are as follows:

Jan 1, 1934

By I. R. Kramer

The stress associated with the high-dislocation layer at the surface of deformed aluminum crystals was measured by progressively polishing the specimen and determining the change in the initial flow stress when the specimen was reloaded. This surface stress increased linearly with strain in the Stage II and Stage III region. The depth to which the high-dislocation layer extends was found to be 0.0025 in. The influence of the surface layer on Stage I is discussed and it is shown that Stage I ends when, on the secondary slip system, the difference between the applied stress and the opposing stress due to the surface layer is equal to the critical resolved shear stress. In previous papers'-3 it was shown that the surface exerts a pronounced effect on the plastic-flow characteristics of metals. For fcc metals it was possible to increase the extent and decrease the slope of Stages I and II and decrease the work-hardening coefficient of Stage II by removing the surface of the specimen continuously during the deformation process.2,3 More recently,L it was shown that the activation energy for plastic deformation and the activated volume were also influenced by the surface. These changes were related to the existence of a high concentration of dislocations in the region near the surface of the deformed specimen and it was concluded' that the effective stress, T, acting on a dislocation was T = Ta-Ti-Ts [1] where 7, is the applied shear stress, Tj is the internal stress, and TS is the stress associated with the surface region containing the high concentration of dislocations. From Eq. [I] it is seen that the effective stress, 7, acting on a dislocation is a function of 7,. Therefore 7, becomes important in any description of the work-hardened state. In this paper the value of 7, as a function of strain and its variation with depth are reported for aluminum single crystals. In particular, it will be shown that the end of Stage I occurs when the net stress, 7, on the secondary slip system is equal to the critical resolved shear stress. To measure Ts, single crystals of aluminum were deformed in tension to various strains, whereupon the load was removed and a known amount of metal was removed by electrolytic polishing. The differ- ence between the final flow stress before the specimen was unloaded and the initial flow stress upon reloading is designated as ?Tp and is the decrease in the stress due to the removal of the surface layer in whole or in part. The value for Tp is taken equal to -Ts. EXPERIMENT PROCEDURE The details of the tensile apparatus, method of electrolytic polishing, and crystal preparation were the same as those used previously,1"3 The single crystals were 1/8 by 1/8 in. in cross section with a 3-in. gage length. The initial purity of the aluminum was 99.997 pet. The specimens were held in vacuo at temperatures 50°C below their melting points for 16 hr and furnace-cooled. Just prior to the application of the tensile stress the specimens were electrolytically polished to remove 0.004 in. from the thickness. This latter operation was conducted after the specimen was placed in the tensile apparatus. The tensile tests were conducted at a strain rate, i, of 10"5 sec-' and a temperature of 3°C. The aluminum crystals used for the determination of 7, are designated A1-3-12 and A1-116. The orientation of the various crystals used throughout the investigation is shown in Fig. 1. The ?Tp values for specimens A1-3-12 as a function of Ax were determined mainly at four strain levels, i.e., ? = 0.0217, 0.0381, 0.0593, and 0.075, where Ax is one half of the total reduction of the thickness after polishing and ? is the re-

Jan 1, 1965

By F. J. Arriagada

A conventional technique used to process auriferous sulfidic concentrates involves a pre-leach oxidative-roast step. The structural characteristics of the calcine have a strong influence on the eventual recovery of gold by cyanidation. Surface analytical techniques such as scanning electron microscopy and BET gas adsorption have been utilized to determine quantitatively the structural morphology of calcined pyrite and arsenopyrite samples in the range of 450 to 750 °C under an oxidizing atmosphere. In the case of. pyrite calcines a highly porous hematite product was found below 500 °C; at higher temperatures, a coarser oxide network , was observed. The surface area of these calcines was found to decrease sharply with increase in temperature. In contrast, the surface area of arsenopyrite calcines was found to follow a bimodal-type behavior with roasting temperature with maxima at 500 and 625 °C. In the case of pyritelarsenopyrite mixtures, the surface area was observed to increase dramatically as the content of pyrite increased. The appearance of pyrrhotite as an intermediate phase in the oxidation reactions is postulated to have important structural implications.

Jan 1, 1984

By T. F. Archbold, W. H. King

THE diffusivities of gold in polycrystalline copper have been determined in the temperature range from 700° to 1000°C by the utilization of the neutron-activation method. Martin, Johnson, and ~saro' used this method for their investigation of the diffusion of gold into copper at 375° and 550°C for 59 days in order to circumvent the experimental difficulties imposed by the 2.7-day half-life of Au-198. They employed the conventional technique of depositing Au-198 on copper specimens for short-time dif-

Jan 1, 1965

By J. C. Williams, M. J. Blackburn

Several of the decomposition processes that can occur in supersaturated phases in a Ti:11.6 wt pct Mo and a Ti:20 wt pct V alloy have been studied by transmission electron microscopy. The deformation induced "marternsitic phase" in the Ti:Mo alloy has been found to have a bcc or bct structure rather than the previously reported hexagonal structure. The morphology of&apos; the transformed region is a rather complex asserrlblage of twins, twinning occurring in one or more systems; this internal twinning has been found to occur on (112). The w phase is formed in both alloys on aging and is present in the Ti:Mo alloy after quenching. The structure of this phase has been confirmed as hexagonal in both systems, however, differences in morphology and stability are found between the two alloys. Thus in the Ti-Mo alloy the w phase has an ellipsoidal morphology with the major axis lying parallel to <111>ß or [0001]w while in the Ti-V alloy the phase forms as cubes, the cube faces lying parallel to {100}ß or {2021}w Some observations on the particle sizes, volume fraction, and composition of the w phase in the Ti-Mo alloy are listed. The mode of formation of The a phase from the (ß + w) structures is also different in the two alloys. In the Ti-Mo alloy the a phase is formed by either a cellular reaction or by the growth of isolated needles, whereas in the Ti-V alloy the a phase is nucleated at an w:ß interface and grow to consume the w phase. Some of the difjerences in behavior of the w phase are attributed to the mismatch between it and the solute enriched ß matrix in which it forms. MaNY transition elements tend to stabilize the bcc or ß-phase when added to titanium. In general two types of phase diagrams are produced, either a ß-stabilized (ß-isomorphous) system, e.g., Ti:Mo, -Ti:V, Ti:Nb, or a ß-eutectoid system, e.g., Ti:Cr, Ti:Fe, Ti:Mn. In previous papers&apos;-4 the phase transformations in the a-phase and (a + ß)-phase alloys have been described and this work has been extended to ß-stabilized systems. Specifically, transformations in the alloys Ti:20 wt pct V and Ti:11.6 wt pct Mo have been studied; in both of these alloys the ß phase is retained at room temperature when quenched from the ß-phase field. A number of phase transformations can occur in such metastable ß phases and the two alloys were chosen to include most of the transformations reported for ß-stabilized systems. We list these possible phase transformations below. Ti:11.6 Mo quenched from >780°C to retain the ß phase: a) The w phase can form on quenching.5 b) Martensite can be produced by subzero cooling or deformation. Two martensite habit planes have been reported in Ti:Mo alloys; (334)ß and (344)ß=6 c) On aging at temperatures <-550° C the w phase is formed before the a-phase.5,7 d) On aging at temperatures >550°C the a phase is formed.7 e) The martensite can be tempered. It has been reported that the a phase rather than the ß phase is precipitated during tempering.&apos; Ti:20V quenched from >660°C to retain the ß phase:9 a) At aging temperatures <260°C separation into two bcc phases occurs. b) The w-phase is produced prior to the a phase on aging at temperatures <-400°C. c) At temperatures 2400°C the a phase is formed directly. T-T-T diagrams describing the temperature and time regimes for the formation of these phases have been published7,9 for a Ti:12 pct Mo and a Ti:20 pct V alloy. We have attempted to investigate these transformations using transmission electron microscopy, however thin foils undergo a spontaneous transformation in all conditions except the equilibrium (a + ß) structure. This transformation has been reported previ0usly10,11 and we will comment on its morphology and nature in the various sections of experimental results. EXPERIMENTAL The compositions in wt pct of the two alloys investigated were: Ti:11.6 Mo, 0.100 02, 0.006 N2, 0.0015 H2 Ti:20V, 0.0574 O2, 0.0111 N2, 0.005 H2 These alloys were cold-rolled to 0.020 in. thick sheet. Specimens were heat treated in vacuum or in inert gas at temperatures >500°C and in a circulating air furnace at temperatures <500°C. Thin foils were prepared using standard techniques, described in detail previously." Dark field micrographs were obtained using high resolution technique. RESULTS Martensitic Transformation in Ti:11.6 pct Mo. Detailed study of the deformation induced martensite is not possible due to a spontaneous transformation which occurs near the edge of thin foils as shown in Fig. 1. Similar transformations have been observed in iron-" and copper-base13 alloys as well as other titanium alloys, but some observations specific to the Ti:1l.6 Mo alloy are listed below. a) The boundaries of these transformed regions are glissile and move under the influence of the electron beam during examination. b) Selected area diffraction indicates the transformed regions have the same structure as the matrix, being separated by tilt boundaries. The misori-

Jan 1, 1969

Most lead-zinc mines worldwide have moved to further mechanized techniques to boost productivity, improve safety, and lower costs. The mining session, chaired by S. C. Fall, NL. Industries, and C. J. Beattie, Callahan Mining Co., reviewed mining methods at five operations in the US, Australia, Peru, and Japan. Where massive sulfide-type and irregular ore bodies are encountered, resourceful operators have modified and varied the mining method with the localized ore zones. In all cases, mechanization of operations has registered gains in productivity.

Jan 11, 1977

. F. W. SPERR, JR.,* Pittsburgh, Pa.--Mr. Malcolmson states that the Carbocoal process produces ammonium sulfate in excess of that normally recovered in the ordinary byproduct coke process. Table 3 indicates that 20,000 to 25,000 lb. of sulfate of ammonia are obtained in carbonizing 1000 tons of Clinchfield coal. This is a high-grade coal and yields from 26 to 28 lb. of ammonium sulfate per ton in a modern byproduct coke oven. On the next page, 21 lb. is stated as the yield of ammonium sulfate per short ton of raw coal; this is less than the average production from any well operated byproduct coke-oven plant treating coal of the character usually coked, in Pennsylvania and Ohio. The statement as to the comparative yields of light oil is somewhat misleading in view of the results obtained during the past year or two by the more modern byproduct coke plants. The plants put in operation by the H. Koppers Co., during the past two years, are producing about 3.5 gal. of light oil per short ton of coal, and several of these plants are producing more than 4 gal. per ton. The yield of pure toluene runs from 0.45 gal. to 0.55 gal. per ton. .The quality of the light oil .obtained from the Carbocoal process is of much greater importance than would be inferred by one not closely familiar with the subject. The presence of paraffins in the benzol and toluol fractions seriously detracts from their commercial value; the benzol and toluol fractions derived fro in the Carbocoal process contain about 50 per cent, of paraffins. It should be thoroughly understood what these paraffins are. They are simply hydrocarbons that go to make up ordinary petroleum, and if a successful method for the removal of paraffins from benzol and toluol has been developed, this can at once be applied to several well known processes by which benzol and toluol can be made directly from petroleum, which have as yet been total failures on account of the contamination of these products by paraffins.

Jan 11, 1918

By E. Escobar Pallares

Footnotes to column heads and explanation of symbols are given on page 239. H.C.T. means the deep zone for High Cold Test crude oil. L.C.T. means the shallow zone for Low Cold Test crude oil. They occur in the same area. In the same area there are many shallow pits and some wells. In the column showing total oil production to the end of 1939 are included 355,997 bbl. from shallow pits before 1939. During the last year there was no production from shallow pita.

Jan 1, 1940

By E. Escobar Pallares

Footnotes to column heads and explanation of symbols are given on page 239. H.C.T. means the deep zone for High Cold Test crude oil. L.C.T. means the shallow zone for Low Cold Test crude oil. They occur in the same area. In the same area there are many shallow pits and some wells. In the column showing total oil production to the end of 1939 are included 355,997 bbl. from shallow pits before 1939. During the last year there was no production from shallow pita.

Jan 1, 1940

By Louis W. Huber

The Liberty tunnels extend through a very steep hill in Pittsburgh (locally called Mount Washington) for a distance of slightly over a mile. The two tunnels parallel each other and are 59 ft. apart, center to center (Fig. 1) They are for vehicular traffic, and in each there is ample space for two lines of vehicles. Northbound traffic, toward downtown Pitts- burgh, is confined to the east tunnel and southbound traffic to the west tunnel. The South Hills residential district is separated from downtown Pittsburgh by Mount Washington, a steeply rising escarpment south of and adjacent to the Monongahela River. The Mount Washington district immediately south of the Monongahela River has been reached, for many

Jan 1, 1927

By Cyril Smith

SEVERAL investigators, mainly concerned with the mechanical proper-ties of the alloys, have studied the so-called aluminum bronzes after various quenching and reheating treatments. Of these works, perhaps the most complete is that of Bouldoires,1 who studied changes of length, electrical conductivity, thermoelectric force, hardness and micro-structure oh tempering quenched alloys containing 5 to 20 per cent of aluminum, although the work of Carpenter and Edwards,2 Curry,3 Greenwood,4 Braesco,5 Matsuda;6,7 Grard8 and others has added much to our knowledge of the changes occurring during tempering. The so-called acicular ß decomposes on tempering at temperatures between 350° C. and the eutectoid, giving rise to a Widmanstätten structure of a needles in a matrix of d or fine a + d, associated with an increase in hardness and almost complete loss of ductility. Matsuda, studied the&apos; eutectoid transformation by means of dilatation and electrical "conductivity measurements during cooling at different rates. He found that on cooling at the rate of 10° C. per minute there was a decrease in electrical resistance and in length instead of the usual increase which occurred with slow rates of cooling. On tempering the rapidly cooled samples, the increase commenced at about 400° C. and at 520° C. the resistance and length had reached the equilibrium values. These peculiarities he accounted for as being due to a transitional phase ß&apos; being formed, ß having an electrical resistance and volume less than either ß or a + d.

Jan 1, 1933

By E. H. Timmerman, A. F. van Everdingen, J. J. McMahon

The prevent paper contains a method which combines the material balance equation&apos; with the water influx equation&apos; to obtain reliable values for the active oil originally in place and a quantitative evaluation of the cumulative water influx. The method is illustrated by an application to a reservoir without original gas cap. In the absence of an original gas cap. results may be obtained using only field production and pressure data, PVT analyses. and a minimum of subsurface information. CHARACTERISTICS OF RESERVOIR AND RESERVOIR FLUIDS Production in the field under review is obtained from the top of the Wilcox formation of Eocene age, at a depth of approximately 8,100 ft subsea. The structural map, Fig. 1, shows that the accumulation, half elliptical in shape with the long axis in east-west direction, is trapped to the north and on the upthrown side of a normal fault. A number of east-west faults with additional minor faulting in random directions are found in the general area, and seismic information and production performance indicate in this particular case the existence of a second fault a short distance downdip, with a strike more or less parallel to the fault controlling the accumulation. It is estimated that 1,830 acres were originally underlain by oil and that the maximum thickness of the original oil column, about 37 ft, was only slightly greater than the maximum thickness of the oil-bearing sand. Maximum net sand thickness was estimated at approximately 26 ft. From logging and subsurface information the gross sand volume has been placed at 37.400 acre-ft. which reduces to about 27,500 acre-ft after probable non-productive intervals have been deducted. The following table presents laboratory analyse; data for the Wilcox sand cores. Average Average Samples Considered Permeability Porosity All Samples 236 md ..19.9percent Samples with k>l md 256 md 20.5 per cent Samples with k>8 md 275 md 20.9 per cent Interstitial water was estimated at 15 per cent. The initial gas-oil ratio was approximately 900 cu ft/bbl. and the initial shrinkage factor was determined by the laboratory to

Jan 1, 1953

By Heinrich Ries

The fusion-point of clay has usually been considered to be influenced chiefly by the quantity of fluxing impurities which the clay contained. Those clays which contain a high percentage of fluxes, such as ferric oxide, lirne, magnesia, and alkalies, fuse at a low temperature. Aside from the percentage of fluxing-impurities, the size of the grains exerts an important influence. Yet, while this fact has, no doubt, been recognized by many, practically no attempts have been made to prove it by actual experiment, although in the case of fire-clays, Prof. H. O. Hofman has rather disputed it. To illustrate the point more clearly, suppose a clay to be made up of a mixture of very refractory grains, such as kaolinite, and some fusible ones. If this clay be heated, the more easily fusible grains will melt first on the surface, and the softening under heat will gradually extend from the surface of the grain to its center. The larger, therefore, the size of the grain, the longer the time required for the heat to penetrate it. Now, if two samples of clay contain the same volume of flux, but of unequal size, the one containing the smaller-sized grains should fuse first, because the fluxing materials are more evenly and thoroughly distributed through the clay, so that they will more or less surround the refractory grains, which tend to act as a framework and hold up the clay-mass when heated. In order to demonstrate the effect of fineness of grain on the fusibility of clay, several mixtures were made up, consisting of white clay and other minerals. The white clay used was a very refractory type from Georgia, the fusion-point of which lay about cone 35 of the Seger series. The mixtures were formed into small bars 1* inches long, and set on a narrow surface, so that the ends were free to bend as soon as the mass softened. They were burned in a Seger gas-furnace.

Jan 1, 1904

By P. K. Koh

With identical annealing heal treatment the development of major annealed texture component seems to depend primarily upon the degree of cold reduction. Cube texture was evident on annealing- 1/2-, 1,/4- , and 1/8-mil tapes at 760°C, but it dissap-)eared on 927°C annealing of 1/8-mil tape cold reduced 96.9 pct. Some cube texturee remained as tile strongest 927 °C annealed texture component in 1/4- and 1/2-mil tapes cold reduced 93.8 and 87.5 pet, respectively. The switching coefficient increases and the squareness ratio of the hysteresis loop decreases proportionally with increasing cube pole concentration. PREVIOUS studies 1,2 on the 1/8-mil ultra-thin molybdenum permalloy tape established cold rolled and annealed textures and their magnetic performance for switch-core and coincident-current memory applications, The major cold-rolled texture was found to be of {110}<335> which is quite similar to the cold-rolled texture of silver and 70-30 cartridge brass. The major annealed texture components were found to be of {120)-- <001> and {113)<785>. Although the direction for easy magnetization for this type of alloy by the single-crystal technique is not avaliable, knowledge from related studies indicated [Ill] as the easy magnetization direction, similar to that of nickel.&apos; Therefore, a cube orientation, if present in the tape core, would be most detrimental to its magnetic performance.3 In its cold-rolled state the tape had < 111 > directions in the rolling plane 14.5 deg from the rolling direction.&apos; But the coercive force of the tape in such condition will be excessive due to large amounts of internal stresses, and therefore makes its use impossible for memory applications due to long switching time. In lower nickel alloys, suchas 50-50 nickel-iron and 65 pct Ni-Fe sheets, previous investigators4"7 found the presence of cube texture on annealing at 900° to 1000°C. Although no cube texture was found in annealed 1/8-mil tape,"&apos; its presence in some annealed 1,/4-mil tape cores was firmly established a year ago as verified by significant differences in magnetic properties. The present investigation is devoted to the orientation study and related magnetic measurements on three thicknesses of the ultra-thin tape, namely, 1/8 mil, 1/4 mil, and 1/2 mil, cold rolled directly from annealed 4-mil stock in the cold-rolled state as well as after they were annealed at 760°C (1400° F) and 927°C (1700°F). The results obtained might serve to elucidate the development of annealed texture as well as to establish clearly the importance of preferred orientation on the magnetic performance of such memory tape core despite its well-known low magnetic anisotropy exchange energy. EXPERIMENTAL PROCEDURE Samples were taken from one production heat (0.010 wt pct C, 0.004 P. 0.016 S, 0.80 Mn. 0.29 Si. 79.69 Ni. 4.42 Mo. 0.054 Co, 0.002 Ti, 0.12 Al, 0.04 Mg, 14.56 Fe). Annealed 4-mil sheets were cold re-

Jan 1, 1962

By Byron E. Eldred

Generally speaking, the practical study of combustion has been made mainly from the stand-point of the steam engineer. This narrow view-point has left open a large field for scientific research on the application of combustion in other arts, where the conditions of heat-utilization are widely different from those presented in the steam-generator. The great economic importance of the boiler and the ease of measuring its performance, together with the comparative uniformity of conditions in the steam-generator, is, probably, quite largely responsible for the practical neglect of the study of the use of fuels in other arts save only on the basis of their thermal value. yet these other arts show quite plainly that a thermal-value basis alone is not sufficient. For example, in burning lime, under ordinary conditions of firing, a cord of wood will do as much work as a ton of coal, though the latter affords more than twice the number of heat-units. Similar results are evidenced in burning brick, in the roasting of certain ores, in reheating billets, and in many other, arts where heat is to be applied over extended areas to fragmental masses of more or less refractory materials. In these arts much is to be gained by a

Jan 1, 1911

By Svend Rordam

THE development of a cement that will resist the destructive action of sea water and other corrosive waters is a problem that has occupied cement chemists for the past one hundred years. It has been found that of the various salts that commonly occur in corrosive waters, sodium sulphate, magnesium sulphate and magnesium chloride are most destruc-tive to cement. Many investigations have been carried out in the United States, in Canada, and in Europe to solve the problem of what constitutes a sulphate-resistant cement, and during the past 10 years some of the findings give definite information in this respect. COMPOSITION OF CEMENT Portland cement is composed of four major compounds: 1. Tricalcium silicate 3CaO.Si02 (C3S) 2. Dicalcium silicate 2CaO.Si02 (C2S) 3. Tricalcium aluminate 3CaO.Al203 (C3A) 4. Tetracalcium aluminoferrite 4CaO.Al203.Fe203 (C4AF) The two calcium silicates are the main contributors of strength. The tricalcium aluminate contributes some to the early strength of the cement but has the least resistance of the four compounds toward the attack of sulphate waters. The tetracalcium aluminoferrite does not contribute very much to the strength, but is far more resistant to sulphate waters than the tricalcium aluminate. When hardened cement is exposed to water containing sodium or magnesium sulphates, these salts will react with the hydrated tricalcium aluminate in the cement and form compounds that will cause a swelling, disruption and crumbling of the hardened cement.

Jan 1, 1939

By J. Chipman, J. C. Fulton

Reduction of silicon from blast-furnace-type slags by carbon-saturated iron is a very slow reaction even under conditions of rapid stirring. Equilibrium under atmospheric pressure of carbon monoxide was approached from both sides, and the silica-silicon relation was established at temperatures of 1425º to 1700°C for slags containing up to 20 pct Al2O3. Silicon carbide is formed by reaction of graphite with high silica slags and the conditions for its formation were determined. Activities of SiO2 and of CaO in their binary solutions at 1600°C were determined. The effects on the activity of SiO2 were established for additions of 10 to 20 pct AI2O3 and of 10 pct MgO. STUDIES of chemical reactions between blast-*>-5 furnace slags and metal have been focussed on the transfer of sulphur from metal to slag. The important role which silica reduction plays in this process&apos; has led to a study of the transfer of silicon from slag to metal and the equilibrium represented by the equation SiO2 (in slag) + 2C (graphite) = Si + 2CO (g). [I.] The authors2 have published an account of the experimental method employed in attacking this problem and of three series of experimental results at 1600°C. This paper contains data on some additional compositions and extends the observations to cover the temperature range 1425° to 1700°C. The data are used to determine the activity of silica in the slags. As in the earlier experiments, the atmosphere was carbon monoxide which flowed through the furnace at 150 ml per min. In certain heats designated in the tables and figures, the gas was bubbled through the melt using a graphite tube. The latter increased in porosity during a run and in some cases bubbling ceased as indicated by cessation of surging. Some results were discarded for this reason. Experimental Results The new data are shown in Tables I through V and both old and new data are plotted in Figs. 1

Jan 1, 1955

By Nicholas J. Grant, Michio Yamazaki

Cast copper alloys containing 10, 20, and 30 pct Ni and 0.75 to 0.80 pct Al were machine-milled into chips, then comminuted in a rod mill to fine flake powder utilizing a number of processing variables. The powders here internally oxidized, mostly at 800°C, in a low-pressure oxygen atmosphere. The consolidated powders were hot-extruded into bar stock. Room-tenmperature tension tests, stress-rupture tests mostly at 650°C, but also at 450° and 850°C, and hardness measurements after various annealing temperature treatments to study alloy stability were perfomted. Excellent room-temperature strength, high rupture strength at 650°C, and resistance to recrystallization at 1050°C were obtained. Problems in optimizing conditions for internal oxidation of Cu-Ni base alloys are discussed. THE interesting high-temperature properties of SAP&apos; have stimulated considerable effort in the study of more refractory alloy systems where the potential for high-strength alloys at high temperature is great.2-13 A number of methods have been utilized to produce the desired fine, hard particle dispersions, of which internal oxidation2,9,7 of dilute solid-solution systems offers considerable promise by virtue of the potential for producing ultrafine, well-dispersed oxides. While most of the published works are concerned with pure metal matrices, a number of investigators have studied the effects of solid-solution strengthening.10,19 Use of more complex alloy matrices (for example, aging systems) has been unsuccessful because overaging still occurs at high temperatures in the oxide-containing alloys.14.15 Solid-solution strengthening is, however, effective at very high temperatures9,10 and might be expected to contribute importantly to the strength of oxide-dispersion strengthened alloys. For this study, internal oxidation of solid-solution alloys of copper and nickel, containing small amounts of aluminum, was chosen as the method of alloy preparation. PREPARATION OF ALLOYS Three copper alloys containing about 10, 20, and 30 pct Ni and each containing 0.75 to 0.80 pct A1 (enough to yield about 3.5 vol pct alumina) were prepared as air-cast ingots measuring 2.5 in. diameter by 6 in. high (see Table I for the analyses). Processing steps for all the alloys were as follows (also see Table 11): 1) Homogenization of the ingot at 982°C (1800°F) for 45 hr in an argon atmosphere. 2) Machine milling of ingots into fine chips. Average thickness was about 0.1 to 0.2 mm. 3) Hydrogen reduction of chips at 593°C (1100° F) for 1 hr to reduce copper and nickel oxides. 4) Rod milling of chips to finer powders. 5) Hydrogen treatment of powders as in step 3. 6) Internal oxidation of the powders. 7) Hydrogen treatment of oxidized powders as in step 3. 8) Hydrostatic compression of evacuated powders. 9) Sintering of compacts in hydrogen. 10) Hot extrusion. Variations in processing among the alloys were made in steps 4, 5, and 10 (see Table 11). In the past, two methods were utilized to internally oxidize alloy powders. Preston and Grant3 surface-oxidized dilute Cu-Al powders to obtain the necessary amount of oxygen to oxidize the solute metal (aluminum and silicon), and then permitted the formed copper oxide to diffuse and react with the solute in an argon atmosphere. Bonis and Grant4 exposed Ni-A1 and other nickel alloys to an oxygen pressure derived from the decomposition of nickel oxide at a preselected temperature, in an argon atmosphere. Both methods are applicable and can be modified to generate a range of oxygen pressures for oxidation of the solute but not the solvent metals. Procedure I: Surface Oxidation of Alloy A3, Cu-10Ni-0.76A1. Powders of -20 to +28 mesh were surface-oxidized at 500°C (932°F) to obtain the desired amount of oxygen for oxidation of the aluminum to alumina; the powder was then sealed in Vycor and heated at 900°C (1652°F) for various times up to

Jan 1, 1965