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By R. E. Miner, J. K. Jackson, T. L. Wilson

A study has been made of the transformation kintetics and morphology in gas-quenched Fe-5 pct Ni alloys. Massive ferrite or nlurtensite was found to form at temperatures in agreement with earlier results. Surface Preparation appeared to have the greatest effect in determining the type of transformation Product formed. Grain size change, subgrain morphology, and dislocation densities of massive ferrite were essen-tinlly invariant functions of cooling rate. The mar-tens~tic structures were typical of transformation in austenite grains of the order of the sample thickness. BY introducing the idea of a massive transformation in dilute iron-base alloys, Gilbert and Owen in 1962 served to stimulate a closer inspection of phase transformations in ferrous systems.' A wealth of literature has followed concerned with the morphology,2-5 transformation mode,2'3'6-8 and thermodynamics of transformations.2,5,9 interesting controversies have resulted from the experimental observations; closer attention has been paid to the definition of massive transformations and still to be resolved is the Ms temperature of pure iron. The purpose of this note is to report some observations made in a detailed kinetic and metallographic examination of the transformations that occur in gas quenched Fe-5 pct Ni. The results are pertinent to the Ms extrapolations that have been made for pure iron and the observed substructure of massively transformed alloys. PROCEDURE The material used in this investigation was cast as a 5 lb vacuum induction melted, carbon deoxidized heat. The ingot was hot worked to a strip 0.10 in. thick, decarburized, and cold rolled to final thickness. Specimens were punched to sample shape and decarburized in wet hydrogen at 600°C. The chemistry of test specimens is indicated in Table I. Samples 1 by $ in., by thickness were resistance heated and rapidly cooled in an apparatus as illustrated in Fig. 1. Similar helium quenching apparatuses have been described previously;2,6'10 the distinguishing feature of this apparatus is the nozzle geometry. Twin nozzles with three convergent-divergent, sonic ports were mounted perpendicular to the specimen for quenching purposes. The specimen temperature was monitored with an intrinsic 3 mil chromel-alumel thermocouple spot welded to the specimen and con- nected to an oscilloscope. A single switch stopped the current flow through the specimen, opened a gas flow solenoid valve, and initiated an oscilloscope sweep. Cooling rates were read directly from a photograph of the oscilloscope trace and the quenching rates quoted later were made at a point immediately prior to transformation on the trace. All quenching studies were conducted either under a vacuum of 10"-5 torr or a helium atmosphere. The sample geometry was chosen large enough to permit optical and electron microscopy to be performed on samples. The samples were electropolished for both types of examination in a perchloric-acetic solution. Electron microscopy was conducted on a HU 11A microscope operated at 100 kv. Dislocation densities were determined at the same general operating reflection (110) on foils thick enough to produce Kikuchi patterns. RESULTS AND DISCUSSION Transformation Temperature Observations and OD-tical Microscopy. The quenching results of this study are illustrated in Fig. -2(a). Samples which were treated in the as-decarburized condition transformed in a manner similar to that reported previously—a decrease in transformation temperature occurred as the quenching rate increased until a plateau region was reached. Within the scatter of the results obtained here, there was no break in the transformation temperature-quenching rate plot. This suggests no change in transformation mode. Further metallographic examination confirmed this observation. A martensitic transformation was obtained for similarly treated samples except that the surface was first electropolished. The Ms temperature was approximately 85°C below the plateau determined for the unpolished samples and cooling rates as slow as 2000°C per sec were adequate for producing marten-site. The transformation temperatures are in gen- / STRIP SAMPLE / COPPER I SAX/-/}' / CONNECTOR-----A f, SON|C poRTS AC LEADS 3j ]j"I rofe[ \ Mf/yinK/iKj''^ THERMOCOUPLE X-(^—iie"s*c? ' LEADS 1 INCH Fig. 1-—Schematic scction of gas quenching apparatus

Jan 1, 1970

By J. W. Downey, A. E. Dwight, R. A. Conner

THE MgCu2 type Laves phase has been observed in the thorium-osmium and thorium-iridium systems. Two alloys corresponding to ThOs2 and ThIr, were prepared by arc melting a 5-g charge in a water-cooled copper. crucible. Both alloys were very brittle. X-ray diffraction patterns were obtained using filtered Cu and Co radiation with a Straumanis-type DeBye-Scherrer camera. The a,, values as shown in Table I were obtained by a Nelson-Riley extrapolation. The structure belongs to space group Oh7-Fd3m. Relative intensities for each of these compounds were calculated on the assumption that 8 thorium atoms occupy (a) positions and 16 osmium or irid-ium atoms occupy (d) positions. The calculated intensities are the product of the Lorentz-polarization factor, the multiplicity factor and F', the structure factor, neglecting the absorption and temperature

Jan 1, 1959

By Arthur Notman

TO present some idea of the magnitude of the gold-mining industry of Canada and the world, the records of 106 gold-mining companies currently paying dividends have been studied. Forty of these are in Canada, and 37 on the Rand in South Africa, these being all the straight gold-mining companies that paid dividends in the two areas in 1938. None of the base-metal companies that produce gold as a by- product, or even as a major fraction of the value of their total product, have beezl included. In addition, a group of 29 similar companies from Southern Rhodesia and the Gold Coast in Africa, India, Australia, Manchuria, Philippine Islands, the

Jan 1, 1939

By W. A. Koehler, W. L. Eaton, Reynold Q. Shotts, M. E. Hinkle, M. R. Geer, Ralph M. Hunter, H. F. Yancey, Andrew B. Crichton, E. Zimmerman, S. H. Ash

R. Maize and H. P. Greenwald presiding) E. T. POWELL*-I would like to ask either Mr. Ash or Mr. Eaton if they know of any place where the Mine Inspectors' for¬mula has been used that water has flowed from one colliery to the other. W. L. EATON (authors' reply)-We have made considerable study but we have not gotten around to very many of the barrier pillars. I would not say that any or all of them have been designed to the strict figures of this formula. Most of those ex¬amined will not hold back the water that they are supposed to hold back. E. T. POWELL-If the pillar remains ac¬cording to the Mine Inspectors' formula? W. L. EATON-We have not found very many where the provisions were followed. E. T. POWELL-Where the Mine Inspec¬tors' formula has been fully complied with, have there been failures or not? W. L. EATON-I cannot say. Most of these barrier pillars probably were designed in accordance with this formula, but most of them, if they were so designed, are not in that shape now because a large number of them will not hold back the water; they have been reinforced, and they are punc¬tured in various places. Holes have been driven through them to relieve the hydro¬static pressure to avoid a failure. They do not dare to have a failure. In many instances, the barrier is punc¬tured to avoid a failure. In order to mine their coal safely, many companies must pump water from mines that were aban¬doned many years ago. R. MAIZE-That is true, Mr. Eaton, but do you know of any case where a barrier pillar actually failed and flooded an ad¬joining mine when the pillar had been left in accordance with the Mine Inspectors formula?

Jan 1, 1948

By AIME AIME

I am happy to welcome you to the twenty-third conference of the National Open-Hearth Committee, and our joint conference with the Blast Furnace Committee, of the American Institute of Mining and Metallurgical Engineers. It is appropriate that, for our fifteenth year anniversary, we should meet in the hotel and the city where this Open-Hearth Committee was inaugurated in 1925. At that first meeting, only a handful of men from a number of steel companies met to discuss ways and means to start a movement to improve the practical and metallurgical technique of open-hearth operations among independent manufacturers, as the United States Steel Corporation had carried on for many years.

Jan 1, 1940

By C. E. Brukl, E. Rudy, St. Windisch

The ternary-alloy system Nb-Mo-C was investigated by means of X-ray, melting point, DTA, and metallo-graphic techniques; a complete phase diagram for temperatures above 1500°C was established. Above 1960°C, niobium monocarbide and the cubic (Bl) high-tenzperature phase in the Mo-C system form an uninterrupted series of solid solutions. The ternary range of the pseudocubic q MoCl-, is very restricted. Dimolyb-denum carbide dissolves up to 44 mol pct Nb2C (2240°C), whereas the maximum solid solubility of MO2C in Nb2C does not exceed 5 mol pct. The order-disorder transformation temperatures in Mo2C and Nb2C are lowered by the mutual metal exchanges. Six invariant (p = const) reactzons occur in the ternary system; three correspond to class 11-type four-phase reactions involving a liquid phase, one to a class I (eutectoid)-type, and two further isotherms are associated with limiting tie lines. The results of the Phase diagram investigation are discussed, and the thermodynamic interpretation identifies the low relative stability of the binary sub-carbides in conjunction with the large stability diflerences between niobium and molybdenum carbides as the cause for the formation of a stable equilibrium between the monocarbide and the metal phase in the ternary reson. Due to their refractoriness, the carbides of the high-melting transition metals have received increased interest in recent years as base materials in composite structures for aerospace applications at high temperatures and for the development of self-bonded cutting tool materials; other novel fields of application include power reactors, where operation at high temperatures becomes essential for attaining high power efficiencies. In these applications, the increased reaction rates at high temperatures require a close consideration of the chemical interactions between the alloy constituents. As a consequence, a detailed knowledge of the phase relationships in the alloy systems is required in order to provide a sound basis for developmental -type work. Partly as a result of the considerable experimental difficulties associated with the investigation of this high-melting alloy class, no complete studies of ternary metal-carbon systems have been performed until recently. Even the high-temperature phase relationships in the binary transition metal-carbon systems have been delineated only during the past few years to a degree of accuracy required for a more detailed study of ternary or higher-order alloys. In recent investigations of binary and ternary systems of refractory transition metals with carbon, boron, and silicon,&apos; alloys from the ternary systems Nb-Mo-C became of interest because of the demonstrated possibility2,3 of obtaining compatible composites based on metal + monocarbide combinations. In the meantime, however, studies in other, but related, ternary metal-carbon systems, such as Ta-W-C, have shown that the solid-state equilibria may change significantly toward higher temperatures (>2000°C), and that extrapolations based on low-temperature equilibrium data are, in general, not very reliable. Although the lower-temperature (<2000°C) phase relationships in the Nb-Mo-C system are similar to those found in Ta-W-C, a cursory thermodynamic analysis of the equilibria indicated4 that complete solid-solution formation between Mo2C and Nb2C should not occur at higher temperatures. The present work was conducted in order to experimentally verify these expectations and, in addition, to provide phase equilibrium data in the melting range of the alloys. In the boundary systems, niobium and molybdenum are known to form a continuous series of solid solutions.576 The continuous solubility was also confirmed by Kornilov and Polyakova,7,8 who also observed a minimum melting point at 22 at. pct Mo and 2345°C. The phase diagram investigations of the Nb-C system by Storms and Krikorian9 and Kimura and Sasaki10 were recently supplemented by Rudy et al.11,12 The system contains a high-melting monocarbide with the B1 structure, Table I, and a subcarbide, Nb2C, which exists in at least two different states of sublattice order at low temperatures47"-&apos;3 and a disordered state above approximately 2500°C.11,12 The melting-point measurements by Rudy et al .11,14 are in close confirmation of the data by Kimura and Sasaki.10 The rather complex phase relationships in the Mo-C system were only recently Clarified.15,18 The system is characterized by three congruently melting, intermediate phases, MozC, ? MoC1-x and a Mol-,, Table I, of which only Mo2C is stable at temperatures below 1650°C. Substoichiometric MozC exists in several states of sublattice order which interconvert in homogeneous phase transitions. Hyperstoichiometric compositions cannot exist in the ordered state. Upon cooling through a critical temperature range, the

Jan 1, 1968

By G. Bruggeman, K. G. Kreider

Grain boundary dij]usion coefficienls were measured in tungsten between 1400° and 2200° C and can be expressed by the equation sq cm per sec This activation energy confirms some eavlier estimates made .from tungsten sintering experiments. Grain boundary diffusion was found to occur in sub-bozrndavies having -misorientations of less than 10 deg. The actiuation energy for this subboundavy diffusion is equal to that for dijjusion in incoherent grain boundaries with in the limits of error. This is shown to be consistent with the dislocation model of Low-angle boundaries wheve diffusion occlcvs along- the dislocation &apos;YPipes" comprising -tile boundary. RECENT investigations of the sintering of tungsten powders all report activation energies which are considerably less than the activation energy for tungsten volume diffusion. Kothari&apos; reports a value of 100 * 5 kcal per mole, Hayden and Brophy&apos; obtained 90 kcal per mole, and Vasilos and smith3 found 110.7 kcal per mole from their sintering studies. Since most determinations of the activation energy for volume diffu-sion4-&apos; fall between 120 and 160 kcal per mole (the true value seems most likely to be nearer 150 kcal per mole), the conclusion is drawn that the mass transport leading to densification during sintering is accomplished by grain boundary diffusion. This interpretation is consistent with various diffusion models of the sintering process. 10-12 Vasilos and Smith calculate diffusion coefficients from their data which fit the equation D * 1.36 x 10* exp(-llO,700/HD However, no direct measurements of tungsten grain boundary diffusion have been made. Furthermore, considerable disagreement exists between the directly measured values of tungsten volume diffusion.&apos;-&apos; In order to corroborate the inferred results of the sintering experiments concerning grain boundary diffusion and to provide accurate diffusion data essential to the analysis of the kinetics of creep, oxidation, precipitation, and so forth, the present work was undertaken to measure self-diffusion in single-crystal and polycrystalline tungsten between 1400" and 2200°C. It is within this temperature range that tungsten sintering is done, the re crystallization of tungsten occurs, and the widest application of tungsten as a high-temperature material will probably be made. EXPERIMENTAL PROCEDURE Radioactive WlE5 was produced by irradiating tungstic acid in a neutron flux of 1.2 x 1012 neutrons per sq cm per sec for 36 hr. A 2-week waiting period was allowed for the decay of w"~ also produced by the irradiation. (w"~ has a half-life of 24 hr.) The half-life of the remaining isotope was determined to be 75 days confirming the presence of w lE5 and the absence of any undesired radionuclide. Specimens 4 in. in diam and $ in. thick were cut from polycrystalline swaged tungsten rods (recrystal-lized) and from Linde single-crystal rods. Chemical analyses of these materials appear in Table I. Actually upon closer examination, the single-crystal specimens were found to consist of several subgrains separated primarily by tilt boundaries in which the misor-ientation ranged from 3 to 10 deg. Thus, it was possible to measure boundary diffusion coefficients in these low-angle subboundaries as well as in the incoherent boundaries of the polycrystalline specimens. The two faces of each specimen were ground flat and parallel within 0.0001 in. The radioactive tungstic acid was dissolved in concentrated ammonium hydroxide, placed on the ground flat of the specimen, and evaporated to dryness. The oxide was then reduced in hydrogen at 1000°C resulting in a layer of wlE5 approximately 1 p thick. The diffusion anneals were performed in vacuum in a tantalum resistance furnace. Time at temperature ranged from 10 hr at 1400°C to 2 hr at 2200°C. The penetration profile was determined by measuring the residual activity after successive removal of surface layers by grinding on metallographic polishing paper. Extreme care was exercised to insure that sections were always taken normal to the diffusion direction; this was verified repeatedly by checking that front and back surfaces of the specimen remained parallel. The activity was measured with an end-window Geiger-Mueller counter. The sides and edges of the specimen were well-shielded to eliminate possible effects due to surface diffusion. The weight of the

Jan 1, 1968

By Allen V. Heyl

This old district is a major zinc and lead source and minor copper and barite source. Ores are chiefly in the Galena Dolomite and in limestones and dolomites of the Decorah and Platteville Formations, all of Middle Ordovician age. Locally, deposits have been mined from Lower Ordovician dolomites and Upper Cambrian sandstones. Small deposits of lead, zinc, and iron sulfides have been found in Upper Ordovician Maquoketa Shale and in Lower and Middle Silurian Edgewood, Kankakee, and Hopkinton Formations. No post-Precambrian igneous rocks are known in the region, and the granitic and metasedimentary Precambrian basement rocks unconformably underlie the district at depths of 1500 to 2000 feet. The strata are gently flexed and faulted, probably largely the result of gentle compressive and rotational adjustments in the underlying crystalline basement, especially along lineaments between basement blocks. Folds of three orders ·of magnitude are recognized, and many related reverse, strike-slip, and normal faults of small to moderate displacements are present. Zinc-lead deposits are commonly linear, arcuate, or elliptical in plan. Most ore occurs as vein fillings in fractures and as breccia fillings and lining vugs, but some is in bedded replacements and impregnations of wall rocks. The ore is in shears, small reverse and bedding- plant faults, joints, and solution-slump structures related to intermediate and small folds. The main primary minerals in their general sequence of deposition are quartz, illite, dolomite, pyrite, marcasite, cobaltite(?), sphalerite, galena, chalcopyrite, millerite, barite, and calcite. Wall-rock alterations include solution of the carbonate rocks, silicification, dolomitization, clay alteration, and sanded dolomite. Oxygenisotope, trace-element, lead-isotope, and sphalerite- stratigraphy studies are in progress. Fluid inclusions in sulfide and gangue minerals are filled with concentrated brines at 120° to 40°C. Sulfides are directly replaced by supergene minerals above the water table at 50 to 100 feet in depth. In this relatively cool climate and limestone environment, smithsonite is in pseudomorphs after sphalerite; solution transport and redeposition of supergene minerals are rare. Ore genesis is postulated by rising hot-water solutions-a mixture of heated connate, magmatic, and meteoric waters.

Jan 1, 1968

By V. Kondic, W. M. Rumball

HUNT and Jackson&apos; have recently suggested that binary eutectics might be classified according to the entropy of fusion of the component phases. Such a classification was in fact proposed2 some time ago by the authors and the purpose of this communication is to present some supporting evidence. As pointed out by Hunt and Jackson&apos; typical metals of low entropy of fusion, ?S, tend to form normal eutectics (using Scheil&apos;s terminology3). Where one phase is metallic (low ?S) and the other nonmetallic (high AS) then anomalous structures are formed. These anomalous structures may either be regular (e.g., Bi-Sn)or irregular (e.g., A1-Si). Finally Hunt and Jackson suggest that where both phases are of high ?S regular faceted structures are formed. In the proposed classification2 the ratio of the entropies of fusion is taken as the quantitative parameter, i.e., ?Sa/?SB = E, where e > 1.0. An extensive literature survey has been carried out2,4 for reliable photomicrographs of eutectic structures. The structures, numbering 151, have been classified into two classes, viz., normal (i.e., lamellar and rodlike) and anomalous. The latter group has been arbitrarily subdivided into regular and irregular anomalous eutectics. Details and sources of the structures are given elsewhere.2,4 In the absence of better thermodynamic data the value of E has been determined for each of the systems making the following assumptions and approximations: l) The entropy of fusion of solid solutions may be calculated additively;5 ii) Inter metallic compounds are treated similarly but with the addition of the following term for fully ordered structures.5 -4.573(Ni lOg10 Nl + N2 log10 N2) where Nl and N2 are the atomic fractions. It might be argued that the entropies of fusion are meaningless as the eutectic phases form at some temperature (T,°K) below their true melting point (Ta or Tb). As AS, = Lo/To if La the latent heat of fusion of a, is assumed independent of temperature, the actual entropy change AS& is given by La/Te. The ratio of entropies of fusion then becomes Fig. 1 shows E&apos; plotted against cumulative totals for normal and anomalous systems from which it is seen that normal eutectics predominate at low values of E&apos;; e.g., some 90 pct of normal systems lie below E&apos; = 1.5 with 65 pct of anomalous systems above this value. Fig. 1 also shows that the regular anomalous structures occur mostly at low values of c&apos; possibly suggesting growth more akin to normal than anomalous growth. The choice of c as a classification parameter was based on nucleation concepts, it being observed that metals widely separated in Sundquist and Mondolfo&apos;s8 nucleation series were anomalous and those close together normal. The basis of these classification views is really outside the intended scope of this communication but it is hoped to explain them fully in the near future.7 Having arrived at this entropy of fusion classification by nucleation considerations it is interesting to note that Hunt and Jackson&apos;s ideas are based on growth considerations. Elsewhere one of the authors4 has shown that an even better classification of the metallographic structures reviewed is obtained from purely conventional heterogeneous nucleation concepts. It has been found that systems having a value of the parameter +b less than 0.28 are almost certainly normal and above this anomalous: V, is the gram atomic volume. This parameter is nevertheless closely related to c and c&apos;, these being an approximation of p. The parameter is also related to the other classification3,8,9 which have met with any success in the past. All these classifications are to be reviewed shortly by the authorsU7 A significant thing about the classifications based on

Jan 1, 1968

By A. E. J. Engel

INDUSTRIAL talcs and ground soapstones both include earth materials of different chemical and mineral compositions. In general, the industrial talcs are composed of silicates that contain appreciable amounts of magnesia. Generally talc, the mineral, is a predominant or at least common constituent. Talc, the mineral, is a hydrous magnesium silicate, with a suggested theoretical formula H2Mg3 (SiO3)4 or H2O.3MgO.4SiO2, which postulates 63.5 pct SiO2, 31.7 pct MgO, and 4.8 pct H20.11 Actually different single grains or leaves of pure talc have variations in water content ranging from 3.5 pct to more than 7 pct, as well as slight differences in the proportions of MgO and Si02.16 Only a very small percentage of the ground industrial talcs produced in the United States approaches the composition given above (see Table 1). The purer talcs invariably occur as alteration products of magnesium carbonate rocks. Some of these relatively pure talcs include compact, massive types largely mined in California, which are designated as steatite.38,58 In general, steatites cannot contain in excess of 1.5 pct CaO, 1.5 pct combined FeO and Fe203, and 4 pct A1203. The less pure varieties of massive talc and mixtures of magnesian silicates are commonly called soapstones, or merely talc. Many industrial earth products classified as talc or as soapstone contain a variety of minerals, especially serpentine (H4Mg,Si2O9), chlorites (hydrous magnesium, iron, aluminum silicates), tremolite (Ca2Mg5H2[SiO3]8), anthophyllite ([MgCa]SiO3), diopside (CaMg[SiO3]2), and quartz (SiO2). The carbonates calcite (CaC03), dolomite (CaMg[CO3]2), and magnesite (MgCO3) are also present in some industrial talcs and soapstones. Some of these minerals, as well as sulphides, sulphates, and iron and manganese oxides, if present at all or in excess of minute amounts, may alter the composition of the industrial talc sufficiently to restrict materially its use or to lower or destroy its value. These factors are discussed in a subsequent section of this chapter.

Jan 1, 1949

By G. L. Fisher, R. Maddin

The rate of self-diffusion in silver single crystals during torsional strain was measured over a wide range of tenperatures and strain rates. The torsional strain was applied in a cyclic manner by reversing the divection of twist aftev a certain fraction of the total strain was reached. Surface roughening was substantially reduced in cyclically strained specimens compared with those strained entirely in one direction. Diffusion coefficients were determined using a special sectioning technique whereby slices could be removed parallel to the surface of a strained torsion specimen. The accuracy of the technique was first determined using roughened specinzens statically diffused to various penetration depths. Simultaneous strain-diffusion experiments were then performed over the temperature range 550&apos; to 800 using strain rates of lo-&apos; to 2.2 x 10&apos; sec-&apos;. The increase in silver self-diffusivity during torsional plastic strain was small. In only one case was the enhancement greater than twice the static value of the diffusion coefficzent. The enhancements increased slightly with decreasing tenzperature and increased with increasing strain rate. A dislocation pipe mechanism of enhancement was found to explain the present results satisfactorily. The magnitude of the enhancements and the tenzperatures at which they were observed suggests that a steady-state dislocation density of 10&apos; to 109 dislocations cm-2 existed during the high-tempevature deformation. The diffusion coefficient in an fcc metal can be increased by 1) an excess concentration of point defects and 2) the rapid movement of diffusing atoms along grain boundaries and dislocations. Plastic deformation may be responsible for enhancements by both of these mechanisms. The results of simultaneous strain-diffusion experiments have caused a controversy over the magnitude of the effect of strain upon diffusion. Experiments reporting large enhancements have been criticized for the manner in which the diffusion coefficient was measured. Several of these experiments have been contradicted by other results obtained in a similar manner. No enhancement was reported by two investigators&apos;&apos;&apos; who performed their experiments at high temperatures where strain is expected to have little effect upon diffusion. A recent theoretical analysis3 indicates that strain enhancement by a vacancy mechanism will be small and exist only at low temperatures and rapid strain rates. It is doubtful whether any experiment has yet proven that strain enhancements can occur by an excess vacancy mechanism. In the present research, experiments were performed at extremes of temperature and strain rate in an attempt to measure enhancement of diffusion by strain. Self-diffusion of silver during torsional deformation was chosen since two separate investigations4j5 indicate that at least a small enhancement exists under these conditions. An accurate method of determining the diffusion coefficient, mechanical sectioning, was employed after a technique was devised to apply it to the roughened surface of a strained torsion specimen. First, the accuracy of the technique was determined for different penetrations (2fi). Then diffusion experiments were performed at temperatures between 550" and 800°C at strain rates of 10"" to 10"" per sec. I) EXPERIMENTAL PROCEDURE Preparation of Specimens. The experimental procedure detailing the growth of crystals, their treatment, and the annealing techniques during straining are contained in earlier publications.496 The dimensions and orientations of the torsion specimens are shown in Figs. 1 and 2. licatiin of Torsional Strain. The torsion procedure was changed from that used previously. The specimens were strained in cycles to reduce the gross distortion and surface roughening inherent in twisting to high strains in one direction. For all strains above 0.30, the total surface strain was obtained as follows: the specimen was twisted to 0.10 strain in a clockwise direction; the direction was reversed; the backlash in the torsion apparatus was taken up; and the specimen was twisted in a counterclockwise direction through the initial starting point to 0.20 surface shear strain in the opposite direction. The strain reversal took no more than 1 min to accomplish. The total accumulated surface shear strain was arbitrarily taken as the sum of the 0.10 strain in the clockwise direction plus 0.20 in the counterclockwise direction. Although cyclic torsional strain was beneficial, surface roughening and specimen distortion were not entirely eliminated. The variation in the diameter at various points on the specimen was often much greater than the depth of the diffusion zone. Since serious errors might result if specimens were sectioned in the usual manner, a technique of lathe sectioning was devised to allow sections to be taken parallel to planes of equal concentration.

Jan 1, 1967

One Hundred Sixteenth Meeting of the Institute, Monday, Feb. 18, to Thursday, Feb. 21, inclusive, 1918 A preliminary program, for the New York Meeting was printed in the January Bulletin, and a more detailed program was mailed to all members early in January. The following schedule is the outcome, of sundry committee meetings up to the middle of January. Committee on Arrangements J.` E. JOHNSON, JR., Chairman BRADLEY STOUGHTON, Vice-Chairman RALPH W. DEACON MRS. S. J. JENNINGS E. M. SHIPP J. V. N. DOER A. R. LEDOUX G. D. VAN ARSDALE L. `V. FRANCIS . . F. T. RUBIDGE ARTHUR L. WALKER Summarized Program MONDAY, FEBRUARY 18 9 a. m. to 5. p. m. Registration at Institute Headquarters. 10 a. m. Sessions on Coal and Non-Ferrous Metallurgy. 12.30 p. m. Luncheon at Engineering Societies&apos;. Building. 2 p. m. Visit to Subway Workings.

Jan 2, 1918

By John G. Tate, George W. Nicolson, James L. Bruce

FOR more than 25 years modern mining has been carried on in the Island of Cyprus, Mediterranean Sea, by the Cyprus Mines Corp. of Los Angeles, Calif. The general features of these operations have been described.1 From 1935 to June 30, 1940, top slicing in the Mavrovouni mine produced in excess of 2,000,000 long tons. The rate for the last part of this period was approximately 50,000 tons per month. DESCRIPTION OF ORE BODIES The shape of the ore body now being top sliced in the Mavrovouni mine is an inclined irregular pyritic pipe or chimney of large dimensions, extending from unknown depths below the bottom level at elevation 250 ft below sea level, to the highest level at elevation 400 ft above sea level. The present surface above the ore body lies between 550 and 650 ft elevation. Undoubtedly the ore body extended to surface and was mined by the ancients by opencast and underground methods. The old pits were gradually filled up by erosion until now they show as slight depressions in the topography. The largest area of the ore body is at elevation 170 ft below sea level, where the horizontal section is almost elliptical, with a width of 600 ft and a length of 1000 ft. Below this elevation the shape of the ore body continues to be elliptical but with reduced dimensions. Above this elevation it rises flatly towards the south with a substantial depression in the upperside of the chimney and irregular ridges or wings rising on each side. It gradually grows smaller as it rises. The ore body is a pyritic replacement of andesitic extrusives which occur as flows and pillow lavas. With the exception of the upper portions of one or two small offshoots rising from the main ore body, all ore is completely surrounded by andesite. Most of the andesite lying above the ore body is covered by marl and clay sedimentaries of Miocene and later age. The Miocene is presumed to be older than the ore mineralization. That portion of the andesites which lies between the sedimentaries and the ore body has been broken by slumpage, and weathered, and iron-stained by the descending meteoric waters. It is a mass of crushed material that caves and follows downward readily as the top-slice stopes retreat. The main ore body is a heavy cupreous pyrites mass assaying on the average about 4.0 pct Cu; 48.0, S; and 42.0, Fe. In places the copper drops below 1.0 pct. On the borders of this heavy sulphide ore body lie disseminated cupreous pyrites ore deposits of large dimensions. Some portions of these appear to be closely related to the heavy sulphide ore, as the ratio of copper to pyrite is about the same. The greater part of the disseminated ore, most of which lies immediately to the east of the main ore body, contains less than 0.10 pct Cu and about 25.0 to 30.0 pct S. This probably can

Jan 1, 1947

By P. C. J. Gallagher

A number of recmt determinations for the ratio of extrinsic to intrinsic stacking fault energy in fcc solid solutions are examined. Some of these arise from incomplete analyses which can yield only approxi?nate values for the ratio. Reliable results, on the other hand, obtained using extrinsic-intrinsic fault pairs, show that the extrinsic and intrinsic fault energies are essentially equal in several materials. There is some reason to believe that this finding is of general applicability to fcc elements and alloys. A wide range of values has been obtained for the relative magnitudes of the extrinsic and intrinsic stacking fault energies (yext and yint, respectively) in recently published studies in a variety of materials. In contrast, Hirth and Lothe&apos; using a central force model have shown that out to tenth nearest-neighbor interactions the perturbation in energy caused by both types of fault is the same. Although the model used is not completely valid in metals, there is nevertheless some indication that marked variations of yext/nnt should not be observed from one material to another. In early work in Cu-A1, Cu-Ge, Ni-Co, and stainless steel all the deformation faults observed in the electron microscope were found to be intrinsic in nature, which led to an attitude that the extrinsic fault energy must be considerably greater than the intrinsic. Extrinsic faulting arising from deformation has, however, more recently been directly observed in Au-4.8 at. pct n;~ Ag-6 at. pct Sn and Ag-8 at. pct sn; Ag-7.5 at. pct In and Ag-11.8 at. pct 1n;"&apos; pure silwer and Ag-0.5 at. pct ~n;&apos; and Cu-22 at. pct Zn, Cu-30 at. pct Zn, and Cu-7.5 at. pct ~1.l&apos; Multilayer loops containing extrinsic faulting have also been observed in quenched aluminum." While peak asymmetries in X-ray faulting probability studies were generally attributed to the presence of twins,Lelel2 has recently reinterpreted earlier X-ray data in Ag-Sb alloysU in terms of the presence of extrinsic faulting. The determinations of yeXt/yint made from the above studies are shown in Table I, with a brief description of the techniques employed. A number of the methods utilized are deficient in one or more respects, and the reliability of the values listed will be discussed. ~ele&apos;~ recognizes that his approximate determinations of yext/yint assumes equal numbers of extrin-sically and intrinsically faulted dislocations. It is well-known, however, that such an assumption is not at all justified since extrinsic faulting has but rarely been observed in samples studied in the electron microscope. The only conclusion that should be drawn from the X-ray results at present is that the total intrinsic scattering cross section (i.e., the product of the width of the intrinsically faulted dislocations with their density) is approximately ten times greater than for extrinsic faulting in these particular samples. An important point is that the relative magnitudes of the energies cannot be inferred from results of this type, unless the intrinsic and extrinsic faults form with equal ease. One must recognize that, although a formation barrier may restrict the amount of extrinsic faulting which occurs, this in no way implies that the extrinsic and intrinsic energies should be different. It is unlikely that a worthwhile estimate of the relative densities of extrinsically and intrinsically faulted dislocations can be made at the high deformations present in X-ray samples. ~oretto,&apos;~ from a statistical argument applied to the nonobservation of extrinsically faulted tetrahedra out of a large sample, concluded that yeXt/yint could not be less than -4.5. However, the present author feels that a high-energy formation barrier as just supposed also explains this finding satisfactorily and that no conclusion can possibly be drawn concerning the actual extrinsic stacking fault energy. The same argument also serves to explain the fact that extrinsic faulting has been relatively little observed in the electron microscope. Extrinsic-intrinsic node pairs and isolated extrinsic nodes were first reported by Loretto~ and subsequently by Ives and Ruff,&apos; Gallaher,&apos; and Gallagher and Wash-burn.&apos; Ives and Ruff&apos; found a wide spread in the ratio of extrinsically to intrinsically faulted area in the node pairs they observed, and drew the very tentative conclusion that yeXt/yint 2 2. They recognized that a straightforward comparison of the size of the faulted areas could provide no more than a qualitative result without a theoretical analysis of the dislocation geometry associated with extrinsic faulting. A theoretical

Jan 1, 1969

SME&apos;s Annual Membership Report - 1961 Membership Directory

Jan 7, 1961

By D. L. Martin

THAT small amounts of impurities have a harm-J- ful effect on the malleability of metals and alloys is well-known. One common type of em-brittlement involves the formation of a small quantity of eutectic at the grain boundaries, and is typified by sulfur embrittlement of nickel. Another example of eutectic embrittlement—sulfur embrittlement of cobalt—is described in this report. In the preparation of specimens for a study of Co-Pt alloys, it was observed that the hot swagabil-ity of the alloys appeared to be influenced by the grade of cobalt used as melting stock. The cause of the hot-shortness was not traced to any particular impurity, although sulfur was suspected.&apos; The damaging action of sulfur on the malleability of cobalt has not been generally recognized,&apos;; in spite of the fact that the Co-S phase diagram8 eveals the same basic conditions—low solubility and eutectic formation—responsible for sulfur embrittlement of iron and nickel.7, 8 Apparently sulfur embrittlement has not been a serious problem in the fabrication of cobalt alloys. One related factor is likely the limited commercial experience with high cobalt alloys, since the predominant use of cobalt has been in alloys containing less than 75 pet Co. A series of Co-S alloys was prepared and studied to establish the effect of sulfur on the hot working characteristics of cobalt. Specimens, 5/8 in. diam by 4 in. long, were prepared by vacuum melting in magnesium oxide crucibles and casting in a copper mold. Two grades of low sulfur electrolytic cobalt were used as the basic material for the study, one from Johnson, Matthey and Co. and the other from the International Nickel Co. Each contained about 99.5 pet Co and had a nominal sulfur content under 0.005 pet. The sulfur was added initially as cobalt sulfide powder. Later, some low sulfur alloys were prepared by diluting the high sulfur alloys with cobalt. Trouble was experienced in controlling the sulfur content. Apparently much of the cobalt sulfide powder was lost during melting, as most of the samples contained a lower sulfur content than was added. The alloys were evaluated for hot brittleness by heating to 1000°C in a hydrogen furnace and swaging in air. The results of these tests are summarized in Table I. All the alloys containing less than 0.008 pet S were successfully hot swaged to 1/4 in. diam. The bars containing more than 0.015 pet S could not be swaged because of the formation of intercrystal-line cracks similar to those illustrated in Fig. 1. Examination of the microstructure of the cast bars revealed cobalt sulfide eutectic at the grain boundaries, Fig. 2. The sulfide was not always continuous at grain boundaries in bars that were hot embrittled but, in general, the particles did form a network that could account for the brittleness above the eutectic temperature, 880°C. There is no question about the brittle nature of a specimen exhibiting a continuous sulfide network such as is shown in Fig. 2b, though a sulfide distribution similar to that in Fig. 2a is marginal. This particular bar cracked when hot-swaged. However, other bars with lower sulfur content but with some sulfide phase at grain boundaries were successfully worked. The reduction of area of a hot tensile test specimen was also found to be a sensitive indicator of sulfur embrittlement. The variation of reduction of area with sulfur content is shown in Fig. 3 for specimens fractured at 900°C in an evacuated capsule. The ductility of cobalt is greatly reduced when the sulfur content exceeds 0.005 pet. Similar results were obtained for alloys tested at 800°C, below the eutectic temperature. The upper sulfur embrittlement limit of 0.015 pet, Table I, agrees with the observation of Kalmus8 hat

Jan 1, 1957

By Frederick Laist

This paper is a review of Montana reverberatory smelting practice covering a period of approximately fifty years, during which time the small furnaces that had been in use elsewhere for a century or more, without much change in size or method of operation, were revolutionized and were developed into the huge, continuously operating furnaces of today. A study of Montana practice is particularly instructive, since reverberatory furnace smelting for the production of copper matte received more attention there than in other smelting centers and many of the improvements that finally resulted in establishing the preeminence of this type of furnace over the blast furnace originated in Butte and Anaconda. The material in this paper was gathered from original sources, wherever possible, and all of the illustrations were made from original drawings, some of which have been simplified and worked over so as to be better adapted for reproduction. The aim has been to trace the modifications in design and operation which took place during the period in question—the reasons for the changes and the results achieved through them. For developments during the first twenty years, the technical literature of the period was freely drawn upon, but I am particularly indebted to W. M. Kelly, general foreman at the Anaconda Works, whose recollections and personal experience extend back to the early days. I wish to acknowledge the use made of publications of E. P. Mathewson, William Wraith and L. V. Bender, as well as information obtained here and there from friends and associates. The resume of Great Falls practice was compiled from correspondence, notes and drawings found in the files of the old Boston & Montana Co. and the tabulations showing the performance of furnaces at Butte and Anaconda are adapted from plant records and correspondence in the files of the Anaconda Copper Mining Company. The paper deals with some interesting comparisons that were made between furnaces operated under various conditions in connection with the Carson Case, and results obtained when using natural gas as fuel. This part of the paper may be considered original to the extent that these results have not previously been published.

Jan 1, 1934

By Paul Weir

FOR the first time in 1938, bituminous coal production for the week ending Nov. 19 surpassed that of the corresponding week in 1937, and indexes of industrial activity indicated the possibility that the remaining weeks of 1938 would run ahead of the corresponding weeks of the preceding year. But regardless of this year-end pickup, total production in 1938 was approximately 25 per cent less than in 1937. The estimate of 340 million tons for 1938 places the bituminous industry slightly above the production level of 1933 and approximately 10 per cent above the modem low of 1932. Anthracite production is not subject to the same extent as is bituminous coal to fluctuations arising out of the rate of industrial activity, hence the decline from 1937 has not been so great being approximately 14 per cent under 1937. The estimate for 1938 production is approximately 45 million tons, but this represents the lowest level reached in the last fifty years with the possible exception of several strike years.

Jan 1, 1939

By R. E. Allen

ONE of the most unusual oil field engineering accomplishments of the past two years is the development and rapid advance in the directed drilling of wells. Directed drilling as referred to herein is the controlled steering of the drill stem in the required direction to a given location in the oil sand. The deliberate drifting of holes is an act so far removed from what has been considered good drilling practice that all of the old questions of correlation, drillability and production difficulties are revived. Only a few years ago, during the boom days of Seminole and Santa Fe Springs, the crooked-hole problem, as it was then called, occupied a primary position among the topics of the day in the fields of California and the Mid-Continent. The net result of all the discussion and study at that time was the conclusion that oil wells should be drilled with as little deviation from

Jan 1, 1933

By Edwin B. Eckel

This paper, based on brief field examination and on data supplied by the operators, records the condition of the Italian mercury industry as of March 1945, not long after Italy&apos;s collapse. Except for the once-Italian but now Yugoslavian Idria mine near Trieste, virtually all the known mercury deposits are in the Monte Amiata district in Siena and Grosseto Provinces, 75 miles north of Rome. This district contains the Abbadia San Salvatore. the Siele. the Argus, and the Cerreto Piano mines besides numerous prospects and unproductive mines. Under pressure from Germany the principal mines were highly productive during the early part of the war, but production fell off long before its end. All of the mines were damaged in some way at the German withdrawal but by September 1944 the Abbadia had resumed production and several others were only lacking power by the early spring of 1945. The Monte Amiata district is characterized geologically by a thick series of sedimentary rocks that range from Triassic to Eocene in age . and are surmounted on Monte Amiata itself by a thick cap of extrusive trachyte. Bodies of travertine and of landslide detritus, younger than the trachyte, are rather widespread. The structure is complex and little known but most of the ore deposits seem to lie along or near a major, north-trending fault or on associated cross-fractures. Cinnabar is the only important ore mineral and clay minerals are by far the most abundant products of hydrothermal alteration. A southward increase in the amount of stibnite, relative to cinnabar, suggests horizontal zoning. The grade of ore ranges from 0.60 to 3.0 Pet and the reserves, as compared with those in American mines, are enormous. Even in the face of war-time scarcities, the mines are remarkably self-sufficient and labor is plentiful, but the costs of production are estimated to be not greatly below those of the better American mines. Notes on the principal mines, on the mining and metallurgical methods, and on the manufacture of synthetic cinnabar are included in the paper. Introduction With but few brief interludes, Spain and Italy, including the Idria mine near Trieste, which has passed from Austrian to Italian to Yugoslavian hands in the Past 3 decades, have led the world in the production of mercury, or quicksilver, for many centuries. Despite their enviable position with respect to the supplies of a metal so essential in both war and peace, there is a notable lack of up-to-date information in America on the mercury industry of either country. Duschak and Schuette&apos; and Schuettez,3 give by far the best summaries in English known to the writer, but the latest firsthand report cited by them on the Italian mines was published in 1915.&apos; Having been deeply interested in the geology and economics of mercury for several years, the writer naturally felt most fortunate in being the to obtain enough firsthand information on the Italian industry to fill at least a few of the gaps in our knowledge. The opportunity came during the war, soon after this industry, together with the rest of Italy, had capitulated to the Allies. Many of the facts presented here are thus definitely "dated," but others are of less transitory nature, and even the dated facts should be of interest in showing the strength and

Jan 1, 1949