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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 J. B. Clark, A. S. Yue

PfANN1 has shown that when a cylinder of molten binary alloy freezes directionally, the solute distribution can be described analytically by cg=k(l-g)k-1 [1] in which Cg is the solute concentration in the solid at the point where a fraction g of the original liquid has frozen and Co is the initial solute concentration. The term k is the effective distribution coefficient of the solute and is defined as the ratio Cx/CL where Cl is the solute concentration in the main body of the liquid. Both the slope and the intercept at -log (1 - g) = 0 of a logarithmic plot of Eq. [I.] provide a measure of k. Under conditions of freezing where diffusion in the solid is negligible and the solute concentration in the liquid is uniform, the effective distribution coefficient k, derived as above, is equal to the equilibrium distribution coefficient taken from the phase diagram. However, under ordinary freezing conditions, even though solid-state diffusion is negligible, the solute rejected from the freezing solid does not have sufficient time to diffuse uniformly throughout the main body of the liquid. A concentration gradient is formed in a boundary layer in front of the advancing solid-liquid interface as pointed out by Rutter and Chalmers.' Thus, under these conditions, the concentration of the freezing liquid in the boundary layer is higher than that predicted from the equilibrium phase diagram and consequently the effective distribution coefficient k, obtained from directional freezing experiments, is larger than the equilibrium distribution coefficient. The symbol k will designate the effective distribution coefficient in the discussion which follows. In this paper, the determination of the effective distribution coefficient is demonstrated for several dilute binary alloys and a polynary magnesium alloy. The effect of freezing rate on the value of the derived k is presented in detail. An example for the calculation of the solidus in a dilute binary solution using the experimentally determined effective distribution coefficient is given. MATERIALS STUDIED Binary magnesium alloys of copper, nickel, and zinc containing approximately 0.10 wt pct solute and a polynary alloy containing approximately 0.10 wt pct each of several elements were selected for study. The spectrographic analyses of these alloys are given in Table I. The analyses are believed accurate to within +5 pct of the stated value. EXPERIMENTAL PROCEDURE Extruded rods of the alloys, 3/8 in. in diam and 11 in. long were used for directional freezing studies. The alloy rods were melted horizontally in a high-purity graphite boat by a Nichrome-wound tube furnace which moved parallel to the length of the rod. The boat was supported inside a Vycor tube suitably connected to provide a protective atmosphere of dry SO2. For an experimental run, the following procedure was used. The alloy rod was cleaned in dilute HNO, and dried. The graphite boat containing the alloy rod was placed within the Vycor tube and the tube connected to the gas train' The 'ystem was purged for 20 min with dry argon and then a flow of dried SO, was maintained for the duration of the run. The movable furnace was positioned and either all or a desired portion of the alloy rod was melted. After attainment of steady-state temperature gradients the molten bar was solidified from one end to the other at a controlled rate by pulling the furnace along the length of the bar at the desired speed. At the conclusion of the run, the directionally frozen alloy rod was analyzed spectrographically at 1 1/4-in. intervals.

Jan 1, 1961

By R. E. Robbins, H. R. Brager

THIS note describes an unusual result obtained in an electron microscope investigation of cavities produced in commercial type 304 stainless steel irradiated in a thermal reactor (ETR) at 290°C to a high neutron flu-ence, 6 x loz1 n per sq cm. The analysis of the steel used is given in Table I. The unusual result is that the calculated quantity of helium gas produced by transmutation during the irradiation, 12 ppm, is less than one-tenth the amount of gas necessary to balance the surface tension of the observed cavities produced in the steel during ETR irradiation. Therefore, the cavities would be expected to behave like voids; however, they behave like "gas filled" bubbles. The maximum quantity of helium produced in the steel by B" transmutation was 8 ppm. In addition, the amount of helium formed by (n, (1) fast neutron reactions with the major alloy constituents and nitrogen was calculated to be 4 ppm based on the tabulated differential or effective fission-averaged cross sections of elements in type 304 stainless steel irradiated in typical thermal reactors.', In previous investigations concerning commercial austenitic stainless steel irradiated in a thermal reactor, the amount of helium gas calculated to be produced by transmutation has always been significantly greater than the amount calculated on the basis that the bubbles were gas filled, PPs= 2y/R. The balance of the gas was assumed to be in bubbles smaller than could be detected on the electron micrographs. Accordingly, the bubbles were attributed to helium produced from transmutation of impurity boron by thermal neutrons. These bubbles were not uniformly dispersed in the matrix but were located principally at grain boundaries, or were radially positioned around a few precipitates located in the matrix and at the grain bundaries., 4 Voids have also been observed in austenitic stainless steel irradiated at high temperature to high neutron fluences in the EBR-I1 and Dounreay Fast Reactors. The voids were uniformly distributed throughout the matrix. The amounts of helium gas produced by transmutation during these irradiations were less than one-tenth the amounts needed to balance the surface tension of the voids formed by the fast reactor irradiation. The fast reactor results are quite analogous to those reported here for the ETR irradiated steel. Electron microscope examination of the fast reactor irradiated material after a 1 hr postirradiation annealing at 900°C disclosed that essentially all the voids had been eliminated. The authors stated that the voids had developed due to the high concentration of vacancies produced during irradiatin., 6, ' The microstructure of the ETR irradiated material as-tested at 75O°C, Fig. 1, contained about 2 X lot5 cavities per cm3 with an average diameter of 110A. With the Van der Waals b correction and y = 1500 ergs per cm2, 300 ppm He would balance the surface tension of the observed cavities. Stereoscopic examination of the electron micrographs showed that the cavities were neither preferentially located near the grain boundaries nor highly concentrated at specific regions or precipitates. The cavities were nearly uniformly distributed throughout the matrix, on dislocations and at grain boundaries. These observations imply that the cavities were not the sole results of B'O

Jan 1, 1969

By F. H. Ellinger

TI HE crystal structure of neodymium has been re-A ported by Quill1 and by Klemm and Bommer"s to be hexagonal-close-packed, Strukturbericht-type A3, with a, = 3.650.4, c, = 5.890.4, c/a = 1.614. Klemm and Bommer,% owever, pointed out that the observed intensities of the lines of the neodymium powder pattern agreed only in part with the intensities calculated for the type A3 structure, and that the neodymium powder pattern showed extra lines which could not be traced to impurities. They found that these extra lines could be accounted for by doubling the c-axis, but apparently they did not consider their evidence to be sufficiently conclusive to justify reporting the doubled c-axis. In the present work, the structure of neodymium was found to be double hexagonal-close-packed. The neodymium metal used in the present investigation was obtained through the courtesy of F. H. Spedding of the Ames Laboratory. Its major impurity was stated to be 0.03 pct Ca. The author's spectrographic analysis indicated high purity and carbon was determined to be less than 30 ppm. X-ray powder specimens were prepared from filings stress relieved in vacuum at 200°C for 50 hr. Powder photographs were taken in an 114.6 mm diam camera (Straumanis film mounting) at room temperature and in a 19 cm diam Unicam high temperature camera at elevated temperatures. Copper x-radia-tion was used for all the photographs. The powder pattern of neodymium was found to index to a hexagonal unit cell with dimensions, as determined from the high angle Ka doublets, of: a.= 3.655+0.001.4; c, = 11.796+0.004.4; and c/a = 3.227 at room temperature. The measured density of neodymium shows that this cell contains 4 atoms, the calculated density is accordingly D, = 7.02 g per cu cm. The diffraction data for the first 15 lines of the powder pattern are listed in Table I. In a double hexagonal-close-packed unit cell, the 4 atoms would be in the positions (0,0,0), (0,0,%), (1/3, 2/3, 1/4), and (2/3,1/3,%) of space group P 6,/mmc. On the basis of these positions, the relative intensities of the reflections were calculated using the expression: 1+cos2 20 I oc \Frp 1 ' sin2 0 cos 0 where F is the structure factor and p is the multi- plicity factor. Since absorption was not taken into consideration, comparison of observed and calculated intensities should be made only for neighboring reflections. Each atom has 12 neighbors, 6 in the basal plane at a distance of 3.655.4 and 3 above and 3 below at the closer distance of 3.626.4. These distances correspond to an average radius of the neodymium atom of 1.820.4. The description of this structure in terms of A, B, and C close-packed layers of atoms is ABAC ABAC. ...... The structure repeats every fourth layer and the stacking sequence of the second, third, and fourth layers corresponds to cubic-close-packing of atoms. A series of powder photographs taken at successively increasing temperatures up to 680a10"C revealed that the double hexagonal-close-packed structure is stable up to this temperature. Acknowledgments The authw wishes to thank W. H. Zachariasen and A. S. Coffinberry for their helpful comments on this work and also Marion Gibbs for measuring the diffraction films. This work was sponsored by the United States Atomic Energy Commission.

Jan 1, 1956

By C. M. Wayman, G. R. Srinivasan

A metallographic study of the isothermal products formed between 750° and 285°C was made in an Fe-7.9 wt pct Cr-1.11 wt pct C alloy, and a time-temperature-transformation diagram was determined. The study shows that the austenite decomposes into three different products: pearlite above 540°C, ferrite and carbide between 540° and 300°C, and lenticular bainite below 300°C. No upper bainite forms in this alloy. The results are discussed in terms of carbon diffusion models for upper bainite formation. AUSTENITE transforms into several products depending on the temperature, composition, and rate of cooling, and the various transformation products have been a source of controversy for a long time. Since the classical study of Davenport and ~ain' extensive work has been carried out. The present study concerns the isothermal transformations in an alloy which was used for a detailed investigation of bainite crystallography and provides information supplementary to the work of Lyman and Troiano who studied austenite decomposition in steels containing 1 pct C and varying amounts of chromium. Their work showed that increasing the amount of chromium in high-carbon steels had the effect of depressing the B, temperature and of shifting the TTT curves to longer times and lower temperatures. They further found that if the chromium content is increased in a 1 pct steel to about 9 pct no bainite would form even after a period of 100 days. However, a preliminary investigation by the present authors showed that bainite plates do form in steels containing about 8 pct Cr and 1 pct C. In view of this and some results from a thin-foil electron microscope investigation of the bainite formed in the present alloy: it was considered desirable to investigate the other isothermal products as well. EXPERIMENTAL PROCEDURE The alloy used in the present investigation was obtained from a triply vacuum-melted ingot prepared from high-purity materials. Chemical analysis for the alloy verified the composition to be Fe-7.9 wt pct Cr-1.11 wt pct C. Metallographic observations were made on i by i by « in. specimens which were aus-tenitized at 12 50°C for 50 to 60 hr in evacuated quartz capsules and then water-quenched. Since the M, temperature for this alloy is below room temperature, the homogenizing treatment produced a completely austenitic structure consisting of very coarse austenite grains (ASTM #0-1). Several samples of the austenitized specimens were metallographically prepared and observed for any proeutectoid carbide separation. It was found that all the carbon was in solution. The water-quenched specimens were upquenched and given isothermal treatments at temperatures between 285" and 750°C for varying periods in molten salt or lead baths. The specimens were then water-quenched, and those showing less than 5 pct transformation were used for plotting the beginning of the austenite decomposition. To ensure the removal of the disturbed layer, the mechanically prepared specimens were electropolished in a 1:6 HzS04, CHSOH solution for 10 to 15 sec at 20 v. Final polishing was done with a vibratory polisher using 0.05-p alumina. Various etchants including nital, ferric chloride, and hot ferricyanide (Murakami's reagent) were used to bring out details in the different transformation products. The ferricyanide etch was used whenever the preferential etching of carbides was desired.

Jan 1, 1969

By W. O. Philbrook, K. Natesan

A mathematical model was derived for the temperature change in a particle undergoing heterogeneous chemical reaction and heal exchange with a stream of fluid. The model has been applied specifically to the exothermic oxidation of spherical particles of zinc sulfide. Very good agreement was obtained between the theoretical prediclion and experimental observation. It was found that at no stage of the reaction was the particle subjected to a state of thermal instability. In studies of gas-solid reactions, it is generally assumed that the gaseous and the solid phases are at the same temperature throughout the reaction period. This is not strictly true since most of the reactions are either exothermic or endothermic in nature. This paper deals only with heterogeneous gas-solid reactions of noncatalytic type. In the case of exothermic reactions (e.g., roasting of sulfides), there may result an increase in temperature of the particle due to the release of the heat of reaction, and this increase in temperature may enhance the reaction rate and thus cause further release of heat. Such a "spiralling" effect may lead to a thermally unstable situation within the particle. On the other hand, in the case of endothermic reactions (e.g., calcination of limestone), there may occur a decrease in temperature of the particle as the reaction proceeds, leading to a virtual "quenching" of the reaction front. A general discussion of autothermic processes with emphasis on properties and reactor design is given by Van Heerden. 1 Levesque and cubicciotti 2 observed self heating of the sample in the oxidation of thorium. Anous et al. 3 observed self cooling of the sample in their dehydration studies on chrome alum. Cannon and Denbigh, 4 and Ong et al.5 reported self heating of the sample in their studies of the kinetics of oxidation of zinc sulfide. A typical plot of heat generation and heat loss rates with reaction temperature is shown in Fig. 1.'14 The Sigmoid curve represents the heat generation rate while the straight lines represent the heat loss rate. The main objectives of this analysis are to estimate the temperature increase of a single particle undergoing an exothermic reaction and to study the possibility of a thermally unstable situation within the particle. Also, a study of the dependence of the tempera- ture increase on different process variables has been attempted. A "she ll-by-shell" method has been proposed to analyze the problem. The shells may be made as small as necessary, and equations may be set up for heat transfer by various mechanisms. Such equations will have to be solved for each shell, with the boundary conditions for ith shell being obtained from the (i - 1)th shell, using a high speed digital computer. The oxidation of spherical particles of zinc sulfide is considered for this analysis, but the treatment is general enough to be applicable to other reactions and particle shapes. The oxidation reaction can be written as AH =« -115 kcal/mole ZnS [1] Such a reaction has been found to proceed in a topo-chemical manner; i.e., as the reaction proceeds, a progressively thicker outer shell of zinc oxide is formed, while the inner core of unreacted sulfide decreases. It has been found experimentally, both in the present work and in the previous investigations,4-6 that the particle retains its original dimensions. Therefore, at any given time, the particle may be

Jan 1, 1970

By John Birkinbine

In the preparation of the paper upon " The Operation of Warwick Furnace, Pennsylvania, from August 27, 1880, to September 1,1885," presented at the Pittsburgh meeting, I purposely refrained from offering theories to explain the peculiarities of furnace operation, on the ground that it was better for those actively engaged in blast-furnace management to present records of operations, than for one more directly interested in blast-furnace engineering and construction to venture upon the sea of speculation as to causes. The manager of an iron-works naturally feels that he knows as much about his particular furnace or furnaces as any one else, and as Mr. Cook, after his close attention to and study of the Warwick furnace, was at that time unwilling to present theories, I felt a disinclination to assume more acumen than the manager.

Jan 1, 1887

ALEXANDER, JOHN S, M,'74-6,'81-3 ASHBURNER, C A, M, '85-7 ASMUS, GEORGE, Dl, '78-80 BACON, D H , M, '00-2 BAYLES, JAMES C , M,'80-2,'91-3 P, '84-5, V,'88-9 BIRKINBINE, JOHN, M, '83-5, V, 'S7-J, P, '91-2 BLAIR, THOMAS S , M, '74-43 BLAKE, WILLIAM P , V,'71-4,'76-7,'05-6 BLANDY, JOHN F, V,'71-3,'78-9 BLOW, A A, C, '05-7 BOWIE, A J , JR, V,'93-4 BRAMWELL, J H , A1, '89-91 BROOKS, THOS B , M, '72 BRUNTON, D W , V, 97-8 BUCK, STUART M , M, '83-5 BURDEN, JAMES A, V,'80-1 BURNHAM, WILLIAM, M, '82-4. CAMPBELL, H H, M, '93-5 CHAMBERLAIN, H S , V, '96-7 CHANNING, J PARKE, V,'08 CHRISTY, S B , V. '91-2, '07-8 CHURCH, JOHN A, M, '79-8l,'94-6, V, '07-8 COGSWELL, W B, V, '74-5,'86-7

Jan 1, 1910

R. Trimble, Pittsburg, Pa (communication to the Secretary) : There are in the proposed specifications only two points on which I wish to comment at this time.

Jan 1, 1902

By M. G. Corson

UNTIL recently, the characteristics of cast copper have seldom been studied and such study as has been made has been inadequate. The prevailing idea seems to be that since pure copper is infrequently used in the cast state, there is no reason for trying to establish precise data regarding the properties of the metal in that condition. On the other hand, wrought copper either in the shape of sheets or wire rarely fails in service, except as a result of the action of reducing gases at the annealing temperatures, so there is little incentive to study the properties of the cast shapes -cakes, bars, ingots and billets-for the sake of tracing the causes of failures of the wrought metal to the cast stock. However, about a decade ago, wirebars of American origin often cracked badly while being hot-rolled in mills in Germany. This led to four investigations: by E. Seidl and E. Schiebold,1 by P. Siebe,2 by 0. Bauer and G. Sachs,3 and by G. Welter.4 These authors came to the conclusion that failures in hot-rolling were due essentially to the presence of a' wide zone of columnar crystals between the thin layer of fine crystals near the surfaces of the bars and the large but more nearly: equiaxed grains of the central core. This macrostructural defect was explained in turn by the probable upward deviation in the temperature of the metal while it was being poured into the molds of the casting machine. More recently, cast shapes of copper were investigated by N. P. Allen5 and by C. Blazey.6 Allen examined vertically cast wirebars and horizontally cast wedge cakes of electrolytic tough-pitch copper, but only for the distribution of densities; i.e., porosity. Blazey was interested mainly in the mechanism of the variations in electrical conductivity due to cold-work and anneal, but gave introductively an account of the composition and average densities of the tough-pitch horizontally cast wirebars used. As far as the present writer can tell, no investigation was undertaken for the sake of presenting a picture of the distribution of mechanical characteristics in the wirebars of copper, tough-pitch or otherwise.

Jan 1, 1938

By J. J. Ormsbee

Attempts at coal-washing have been made in the southern states during the last twenty years; but it is only within the last four or five years that the practice has become at all general. It might perhaps be claimed as one of the blessings derived from our departed " booms;" for, during their sway, the supply of coal of all qualities, good and bad, could not equal the demand; but, with the subsidence of the inflated demand, came imperative calls for fuels of better quality; and washers, previously regarded as luxuries, became necessities. Among those now in use in this section are representatives of the following types or classes: the trough washer; the jig washer; the percussive table; and those washers in which a constant upward current of water effects the separation. Without having full statistics, it is safe to say that there are in successful operation in the South more washers of the last class than of any of the others. The purpose of these notes is to present data with regard to the constructiOn, operation, and results of one of these current-washers, based mainly on the plant at No. 2 Slope, Pratt Mines, Alabama. The coal is mined from the well-known Pratt seam, having here an average thickness of 3 feet 6 inches. It has distinct cleavage-planes, and breaks in cuboidal lumps; is bright black in color, firm in structure, and air-slacks only after considerable exposure. It burns freely, leaving a gray or buff-colored ash. The lump- and nut-coals are used for domestic and steampurposes (chiefly, however, for locomotive firing), and the slack for making coke. The specific gravity is 1.272. Analyses of Pratt Coal. I. 11. 111. IV. Min. Resources Authority. Phillips. McCalley. of U. s.,1892. Lupton. Fixed carbon,. . 67.90 61.600 64.30 63.82 Volatile material,.. 29.80 31.480 32.08 31.85 Moisture,.,...... 1.508 1.07 1.02 Ash,.... 2.30 5.416 2.08 3.31 Sulphur,. .. 0.83 0.918 0.47 0.70

Jan 1, 1896

By A. C. Callen

This, report represents the comments of the individual members of the A. I. M. E. Sub-committee on Physics of Mine Ventilation on the proposals of a special committee of the Institution of Mining Engineers (London). As might be expected, there is a certain diversity of opinions, for owing to the shortness of time- it was not possible for the sub-committee to get together for informal discussion. The report is presented in this form in the hope that it will bring out a full discussion by other members in the Institute. OLE SINGSTAD?, New York, N. Y.-The Atkinson formula, P =SV2 K a is quoted and it is stated that this formula is especially applicable to mine galleries but is unwieldy in application, as in many problems the value of K, S and a are assumed not to change. This is the same formula that was used during the preliminary calculations for the ventilation of the Holland Tunnel, and where the above-mentioned values were constant for a number of cases, it was a very simple matter to rewrite the equation n the form P = K1V2 and avoid the repeated use of identical figures. The Atkinson formula assumes 1. That resistance to flow is independent of the pressure. 2. Changes in volume due to change in pressure may be neglected. 3. Changes in density and viscosity may be neglected. 4. That the coefficient K is a constant. 5. That P is proportional to V2. We found, from our experiments in connection with the ventilation of the Holland Tunnel, that all the above assumptions could be safely made, with the exception of No. 3, and No. 4 at, very low velocities. In mine work, where many assumptions must necessarily be made, it would seem inconsistent to attempt to make any allowance for the other factors, which are so small that they can be determined only by the most careful experimental work. However, P does depend directly on the density of the air, and to that extent the Atkinson formula is incomplete.

Jan 2, 1926

ALEXANDER, JOHN S, M,'74-6,'81-3 *ASHBURNER, C A, M, '85-7 ASMUS, GEORGE, Dl, '78-80 BACON, D H , M, '00-2 BAYLES, JAMES C , M,'80-2,'91-3 P, '84-5, V,'88-9 BIRKINBINE, JOHN, M, '83-5, V, 'S7-J, P, '91-2 BLAIR, THOMAS S , M, '74-43 BLAKE, WILLIAM P , V,'71-4,'76-7,'05-6 *BLANDY, JOHN F, V,'71-3,'78-9 BLOW, A A, C, '05-7 BOWIE, A J , JR, V,'93-4 *BRAMWELL, J H , A1, '89-91 BROOKS, THOS B , M, '72 BRUNTON, D W , V, 97-8 BUCK, STUART M , M, '83-5 *BURDEN, JAMES A, V,'80-1 BURNHAM, WILLIAM, M, '82-4. CAMPBELL, H H, M, '93-5 CHAMBERLAIN, H S , V, '96-7 CHANNING, J PARKE, V,'08 CHRISTY, S B , V. '91-2, '07-8 CHURCH, JOHN A, M, '79-8l,'94-6, V, '07-8 COGSWELL, W B, V, '74-5,'86-7

Jan 1, 1910

By Frank Foote, Eric R. Jette

In a recent article,1 the authors reported the results of an X-ray investigation on the range of solid solutions that occurs in the iron-oxygen system in the vicinity of the compound FeO, which frequently is called "wüstite." The object of that investigation was primarily to study the unusual type of solid solution phenomena involved in this range. Briefly summarized the results were: 1. The NaCl type of lattice found by earlier workers was confirmed. 2. The lattice dimensions decrease rapidly with decrease in iron content. 3. No alloy that was a homogeneous single phase was ever found at compositions beyond 76.80 per cent Fe, while the theoretical iron content of FeO is 77.73 per cent Fe. 4. Measurements of the densities and lattice constants led to the conclusion that the form of substitution was complex, an FeO group being replaced by oxygen. Such a substitution, of course, is equivalent to removing an iron atom (or ion). The ideal unit cell of FeO can be considered as containing four groups of FeO and, thus, when this type of substitution takes place, there remain in the unit cell three FeO groups and an oxygen, or a total of seven atoms with a gross formula of Fe3O4 instead of the original Fe4O4. 5. This was the only interpretation that would fit the experimental results and at the same time be consistent with (a) the previously determined fact that the FeO lattice is ionic (i, e., consists of Fe++ and O? ions) and (b) the chemical fact that as the oxygen content of the substance increases, ferrous iron becomes oxidized to ferric iron. The experimental results of this investigation are included in Fig. 1. The purpose of the present investigation was to determine the limits of this homogeneity range by means of the X-ray structure analysis. This method has been applied frequently to the study of solid solutions by Westgren and his coworkers as well as by other investigators. The principle is simple: if the change in lattice constant with composition is

Jan 1, 1933

Powder Metallurgy Committee Local Sections DETROIT Robert Henderson, President, Victor Gallatin, Vice-President, Secretary, J I Farmer, Treasurer John Check, NEW YORK K H Roll, Chairman

Jan 1, 1957

By A. Eilers

I PRESENT herewith, for the inspection of the members of the Institute, a specimen of coke, made in gas-retorts from the lignite of Trinidad, Colorado.

Jan 1, 1874

By A. Eilers

I present herewith, for the inspection of the members of the Institute, a specimen of coke, made in gas-retorts from the lignite of Trinidad, Colorado.

By R. M. Brick, M. A. Williamson

Certain features of the response of copper and brass to deformation and recrystallization remain obscure. The textures obtained on rolled sheet are listed by Schmid and Boas1 as: No adequate explanation has been advanced for the presence of the secondary deformation texture of copper and its absence in brass or for the origin of the cubic recrystallization texture of copper.2 A recent publication3 attempted to rationalize the above empirically described annealing texture of brass on the basis of retention of the (110) [112] rolling orientation plus twinning about the central octahedral poles of the usual secondary (110) [115] orientation. The difierence in the textures of annealed copper as compared to 70-30 brass is also shown by the difference in the position of ears for drawn copper, at o° and go", as compared with drawn brasses, at 45o, for all compositions between oo-10 and 70-30.4 Data on indi- vidual crystals are as yet too few to permit of an analysis of these textures comparable to that of mild steel as made by Barrett and Levenson.5 Experimental Methods The materials studied included copper specimens cut from the central, equiaxed crystal portion of a tough-pitch wirebar; brass made from this copper and high-purity (99.99 per cent) zinc including alloys of 7 per cent, 15 per cent, 24 per cent, 29 per cent and 36 per cent Zn and large single crystals of 70-30 bras. Sections 1/4 in. thick of the cast polycrystalline copper and brasses were reduced 40 per cent by rolling, recrystallized to a common grain size of 0.045 mm. and then rolled directly to foil 0.002 in. thick. Hardness readings employing both the Vickers and Rockwell machines were taken at intervals during the reduction. For comparison, similar specimens were cross-rolled—i.e., turned through 90° for each pass—and comparable hardness data were secured. Finally sections from the single crystals of brass were cut to obtain the following initial orientations; these sections were rolled, hardness data secured and a complete micrographic record of structural changes obtained.

Jan 1, 1941

By R. M. Brick, M. A. Williamson

Certain features of the response of copper and brass to deformation and recrystallization remain obscure. The textures obtained on rolled sheet are listed by Schmid and Boas1 as: No adequate explanation has been advanced for the presence of the secondary deformation texture of copper and its absence in brass or for the origin of the cubic recrystallization texture of copper.2 A recent publication3 attempted to rationalize the above empirically described annealing texture of brass on the basis of retention of the (110) [112] rolling orientation plus twinning about the central octahedral poles of the usual secondary (110) [115] orientation. The difierence in the textures of annealed copper as compared to 70-30 brass is also shown by the difference in the position of ears for drawn copper, at o° and go", as compared with drawn brasses, at 45o, for all compositions between oo-10 and 70-30.4 Data on indi- vidual crystals are as yet too few to permit of an analysis of these textures comparable to that of mild steel as made by Barrett and Levenson.5 Experimental Methods The materials studied included copper specimens cut from the central, equiaxed crystal portion of a tough-pitch wirebar; brass made from this copper and high-purity (99.99 per cent) zinc including alloys of 7 per cent, 15 per cent, 24 per cent, 29 per cent and 36 per cent Zn and large single crystals of 70-30 bras. Sections 1/4 in. thick of the cast polycrystalline copper and brasses were reduced 40 per cent by rolling, recrystallized to a common grain size of 0.045 mm. and then rolled directly to foil 0.002 in. thick. Hardness readings employing both the Vickers and Rockwell machines were taken at intervals during the reduction. For comparison, similar specimens were cross-rolled—i.e., turned through 90° for each pass—and comparable hardness data were secured. Finally sections from the single crystals of brass were cut to obtain the following initial orientations; these sections were rolled, hardness data secured and a complete micrographic record of structural changes obtained.

Jan 1, 1941

By A. Kelly, S. Sato

Tensile tests have been performed on aluminum single crystals of 99.99 pct purity at 196°K. The resolved shear stress when the stress-strain curve becomes concave to the strain axis depends on orientation, being always higher for crystals with an initial orientation close to the sides of the unit triangle. Observations have been made, with the optical microscope, of the appearance of slip lines on polished surfaces of the crystals. Particular attention has been paid to the first appearance of cross-slip. It is confirmed that marked cross-slip is first seen when the stress-strain curve becomes concave to the strain axis. Measurements are reported of the lengths of the slip lines observed on top and side faces of the crystals at various stages of the deformation. The lengths of the slip lines vary inversely as the flow stress for all crystals, independent of crystal orientation. From measurements of the lengths and separations of the slip traces it is possible to estimate the number of dislocations which are annihilated at each cross-slip site. It is concluded that the annihilation of screw dislocations of opposite sign is the most important cross-slip process occurring. FRIEDEL1 recently pointed out that the stress-strain curve of many pure metals of face-centered-cubic structure can be considered as composed of three stages. Plastic flow commences with a region showing a small rate of hardening which is approximately linear. This has been called "easy glide*. It is followed by a region of more rapid hardening in which the slope of the curve is again approximately constant and this, in turn, is superseded by a final part of the curve which is concave to the strain axis. Following Diehl2 we may designate these regions as stages I, II, and III respectively. The onset of stage 111 occurs at lower stresses at higher temperatures. The appearance of the slip lines formed during these various stages has been described by a number of workers?-5* The object of the present work was to make detailed observations of the lengths and separations of slip lines for a number of crystals of different orientations deformed at the same temperature and strain rate. Although much previous work has been published on the deformation of aluminum single crystals the importance of measurements of these quantities has only recently been realized—they are essential for experimental tests of recent theories of work hardening.' 9 In aluminum, deformed at room temperature, stage 11 of the stress-strain curve is very weakly marked, as the stress for the onset of stage 111 is attained soon after the end of easy glide. In the present experiments it was decided to use a temperature lower than room temperature so that stage II of the curve was better developed. However, at temperatures as low as 90°K slip lines are not measured easily with the optical microscope.5 For this reason 1960k was chosen as a suitable temperature. Even at 1960k however, stage III of the curve commences at glide strains of 6 to 10 pct and hence

Jan 1, 1960