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By J. B. Dyess

TARNISH films on some of the common metals (particularly on copper and silver) have been of much scientific and commercial concern for a long time, but before the development of the electrical method1 of measuring film thicknesses there was no satisfactory quantitative approach by which to study the separate parts of these complex films. This method has been adapted to the measurement of duplex (cuprous-cupric) oxide films on copper .2 In the present work it has been used to measure tarnish films on copper when they were mixtures of cuprous oxide and cuprous sulphide, and also when they contained cuprous oxide, cupric oxide and cuprous sulphide, each component part being measured at a different potential value. Oxide-coated copper specimens, prepared by heating copper in air at chosen temperatures for given periods, were exposed to moist hydrogen. sulphide in air to form the various oxide-sulphide films studied. The comparative resistances afforded by (1) different thicknesses of oxide films, and also (2) equal thicknesses of oxide and sulphide films, against severe attacks of hydrogen sulphide were measured. The electrical method requires that the time be observed for the cathodic reduction of each part of the film substance, and these respective time values multiplied by the constant current give the corresponding quantities of electricity expended. Then each millicoulomb per square centimeter represents a film thickness of T= MX10 8 2D X 96,494 X 103 (a) where M is weight of oxide (or sulphide) giving one gram-atom of oxygen (or sulphur) for cathodic reduction, D is density of the oxide (or sulphide) and t is the thickness in Angström units per millicoulomb per square centimeter. The value of t for cuprous sulphide (cubical) is 14.27, and is obtained by substituting 5.78 for D and 159.20 for M in equation a. Previous values2 of t for cuprous and cupric oxides (12.36 and 6.39, respectively) were used in the present work.

Jan 1, 1939

By David A. Summers, Clark R. Barker, Marian Mazurkiewicz

In May 1975 the U.S. Bureau of Mines contracted with the University of Missouri-Rolla, Rock Mechanics and Explosives Research Center to develop a Hydrominer modification to a longwall shearer unit, wherein the rotating pick-laced drums and connecting gear drives are replaced by a water jet cutting ahead. The concept of the water jet cutting head is based on using the high localized energy of the water jets to isolate a slice of coal by cutting a slot under, at the back of, and at the top of the web. The plow blade of the head then advances into the cut and wedges the coal cantilever over onto the conveyor [(Fig. 1)]. There were several potential advantages foreseen for the system; perhaps the most significant were the elimination of coal dust from the working area and the ability, with a variation in nozzle geometry, to cut webs of greater depth with a small increase in haulage horsepower. The University initially designed the head, based on experiments carried out in the laboratory, under an earlier Bureau of Mines contract. The experiments showed that it was more advantageous to work at a pressure of 68.9 mPa (10,000 psi) with an estimated flow rate of 3.15 X 10 - 8 m3/s (50 gpm) than go to the higher pressures and lower flow rates which have been advocated elsewhere.

Jan 1, 1979

[PRESIDENT SAMUEL A. TAYLOR, . . . . District 3 . . . . PITTSBURGH, PA. PAST PRESIDENTS WILLIAM KELLY, District 5 . IRON MOUNTAIN, MICH. J. V. W. REYNDERS District 3., NEW YORK, N. Y. FIRST VICE-PRESIDENT E. DEGOLYER, NEW YORK, N. Y. TREASURER CHARLES F. RAND, NEW YORK, N. Y. SECRETARY H. FOSTER BAIN, NEW YORK, N. Y. ASSISTANT SECRETARY THOMAS T, READ, NEW YORK, N. Y.]

Jan 1, 1928

By Nathaniel Arbiter, Arthur F. Taggart

THE chemical reaction occurring in collection of nonmetallic minerals with amine-type collectors was early postulated by students of flotation phenomena to be metathesis between the mineral and the collector, involving exchange between the amine-bearing (aminium) ion and the cation of the mineral, and formation at the mineral surface of an oriented film of the amine salt of the mineral anion. Qualitative evidence of exchange has been obtained on several occasions at Columbia. Thus 1000 c.c. of a solution containing 495 mg. of laurylamine hydrochloride was shaken 17 min. with 100 grams of barite and ground in a porcelain mill to pass a 200-mesh screen; the mixture was then set aside for 48 hr. Filtrate therefrom analyzed 476 mg. per liter of laurylamine hydrochloride. There was no substantial loss of chloride ion (78.4 mg. per liter in the original; 74 in the filtrate). No successful analyses were concluded for barium ion. Earlier, confessedly rough work with scheelite indicated a solution gain in Ca++ equivalent to about one-half the aminium ion lost. Real quantitative proof of the exchange, in the form of an established stoichiometric balance, is unknown to the authors. The data of the present paper, however, obtained from experiments designed on the basis of the exchange hypothesis, constitute strong evidence of its truth, and at the same time point the way to economic utilization of the expensive nitrogen-bearing collectors in concentration of the low-priced nonmetallic minerals. The basic postulate underlying the experiments performed was that, if the collecting reaction is of the type [R+ + Y- + MX =± RX + M+ + Y¬] where R = aminium ion, Y = the anion of the amine salt, and M and X are, respectively, the cation and anion of the mineral, the reaction should obey qualitatively the implications of the massaction and solubility-product laws. This is to say that coating and collection should be aided by the addition to the solution of either ion (R+ or X-) of the collector-coating compound, and hindered by the addition of either of the ions M+ or Y-. Experimental work comprised determination of (1) the relative solubilities of the laurylammonium salts of a variety of nonmetallic-mineral anions; and (2) the contact angles1 of various minerals in solutions containing different concentrations of the postulated controlling ions. Semiquantitative flotation tests were run with barite as checks on the diagnostic character of the contact angles. The amine

Jan 1, 1944

By T. H. Aldrich

THE Aldrich Mining Co. holds under lease from the Illinois Central R. R. Co. about 14,000 acres, in the East half of Township 12, Range 12 `V., in Marion county, Alabama, and owns other lands, of which about 1,000 acres adjoin this leased tract, making a total area of about 15,000 acres, all of which is underlain by the coal-seam upon which the company is operating. This seam is nearly horizontal ; and a ravine, diagonally crossing the tract, exposes the outcrop on either side for about 2 miles. The territory has been so divided that nearly the whole of it can be worked out by two collieries. The mines at Brilliant were opened in the Fall of 1898, and shipments began in the following spring. The original plan was to furnish steam-coal for locomotives to the Illinois Central R. R. Co.; and upon this expectation the investment of capital was made. The field was entirely new; and the softness of the coal at the outcrop induced the belief that it could be very cheaply mined. A contract for the delivery of a large quantity of coal to the railroad was accordingly executed. But with the advance of the entries to increasing distances from the outcrop, the coal proved so hard that it could no longer be drilled with a breast-auger; and the expense of mining became so great that the contract for cheap steam-coal had to be cancelled. It became evident that the work must be done with machinery and explosives, if it could be profitably done at all. On the other hand, the excellent quality of this coal opened, at the same time, a possible market not specially contemplated at the outset-namely, that of a first-rate coal for domestic and general uses. Since no other deposit of such coal was known to exist on the line of the Illinois Central, or any other railroad

Jul 1, 1906

By C. C. Harris Discussion by B. K. Loveday

B. K. Loveday (National Institute for Metallurgy, Johannesburg, Republic of South Africa) - The paper and subsequent technical note' describing a method of determining the parameters of the three-parameter size-distribution equation developed in the paper were read with much interest. This equation was also used at National Institute for Metallurgy (NIM) to describe size distributions in grinding tests, because it was necessary to have a single equation to describe the size distribution at any time during a test. A graphical method also was used to determine the three parameters, and the use of this method as an alternative to Professor Harris's latest method is discussed here. The three-parameter model can be expressed as follows: Eq. 1 can be rearranged and transformed to Yield a linear reiationship between Y and X (transformed) log

Jan 1, 1970

By A. F. Taggart, Nathaniel Arbiter

The chemical reaction occurring in collection of nonmetallic minerals with amine-type collectors was early postulated by students of flotation phenomena to be metathesis between the mineral and the collector, involving exchange between the amine-bearing (aminium) ion and the cation of the mineral, and formation at the mineral surface of an oriented film of the amine salt of the mineral anion. Qualitative evidence of exchange has been obtained on several occasions at Columbia. Thus 1000 C.C. of a solution containing 495 mg of laurylamine hydrochloride was shaken 17 min. with 100 grams of barite and ground in a porcelain mill to pass a 200-mesh screen; the mixture was then set aside for 48 hr. Filtrate therefrom analyzed 476 mg. per liter of laurylamine hydrochloride. There was no substantial loss of chloride ion (78.4 mg. per liter in the original; 74 in the filtrate). No successful analyses were concluded for barium ion. Earlier, confessedly rough work with scheelite indicated a solution gain in Ca++ equivalent to about one-half the aminium ion lost. Real quantitative roof of the exchange, in the form of an established stoichiometric balance, is unknown to the authors. The data of the present paper, however, obtained from experiments designed on the basis of the exchange hypothesis, constitute strong evidence of its truth, and at the same time point the way to economic utilization of the expensive nitrogen-bearing collectors in concentration of the low-priced nonmetallic minerals. The basic postulate underlying the experiments performed was that, if the collecting reaction is of the type R+ + Y- + MX = RX + M+ + Y- where R = aminium ion, Y = the anion of the amine salt, and M and X are, respectively, the cation and anion of the mineral, the reaction should obey qualitatively the implications of the mass-action and solubility-product laws. This is to say that coating and collection should be aided by the addition to the solution of either ion (R+ or X-) of the collector-coating compound, and hindered by the addition of either of the ions M+ or y-. Experimental work comprised determination of (,) the relative solubilities of the laurylammonium salts of a variety of nonmetallic-mineral anions; and (21 the contact angles' of various minerals in solutions containing different concentrations of the postulated controlling ions. Semiquantitative flotation tests were run With barite as checks on the diagnostic character of the contact angles. The amine

Jan 1, 1947

By Nathaniel Arbiter, A. F. Taggart

The chemical reaction occurring in collection of nonmetallic minerals with amine-type collectors was early postulated by students of flotation phenomena to be metathesis between the mineral and the collector, involving exchange between the amine-bearing (aminium) ion and the cation of the mineral, and formation at the mineral surface of an oriented film of the amine salt of the mineral anion. Qualitative evidence of exchange has been obtained on several occasions at Columbia. Thus 1000 C.C. of a solution containing 495 mg of laurylamine hydrochloride was shaken 17 min. with 100 grams of barite and ground in a porcelain mill to pass a 200-mesh screen; the mixture was then set aside for 48 hr. Filtrate therefrom analyzed 476 mg. per liter of laurylamine hydrochloride. There was no substantial loss of chloride ion (78.4 mg. per liter in the original; 74 in the filtrate). No successful analyses were concluded for barium ion. Earlier, confessedly rough work with scheelite indicated a solution gain in Ca++ equivalent to about one-half the aminium ion lost. Real quantitative roof of the exchange, in the form of an established stoichiometric balance, is unknown to the authors. The data of the present paper, however, obtained from experiments designed on the basis of the exchange hypothesis, constitute strong evidence of its truth, and at the same time point the way to economic utilization of the expensive nitrogen-bearing collectors in concentration of the low-priced nonmetallic minerals. The basic postulate underlying the experiments performed was that, if the collecting reaction is of the type R+ + Y- + MX = RX + M+ + Y- where R = aminium ion, Y = the anion of the amine salt, and M and X are, respectively, the cation and anion of the mineral, the reaction should obey qualitatively the implications of the mass-action and solubility-product laws. This is to say that coating and collection should be aided by the addition to the solution of either ion (R+ or X-) of the collector-coating compound, and hindered by the addition of either of the ions M+ or y-. Experimental work comprised determination of (,) the relative solubilities of the laurylammonium salts of a variety of nonmetallic-mineral anions; and (21 the contact angles' of various minerals in solutions containing different concentrations of the postulated controlling ions. Semiquantitative flotation tests were run With barite as checks on the diagnostic character of the contact angles. The amine

Jan 1, 1947

PRESIDENT. CHARLES F. RAND,1 NEW YORK, N. Y. PAST PRESIDENTS. CHARLES KIRCHHOFF,1 NEW YORK, N. Y. JAMES F. KEMP,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT. BENJAMIN B. THAYER,1 NEW YORK, N. Y. TREASURER. GEORGE C. STONE,1 NEW YORK, N. Y. SECRETARY EMERITUS. ROSSITER W. RAYMOND NEW YORK, N. Y.

Jan 5, 1913

By David Cole

THE New Cornelia Copper Co. is mining and treating a 'monzonite " porphyry" copper deposit that is all hard rock. The oxidized surface shell, which constitutes the leachable part of the orebody, is measurably more resistent to crushing and comminution processes than is the underlying sulfide portion. The siliceous ribs running through the whole orebody are harder to crush than the main mass and there is no soft crumbly material to furnish the large volume of primary fines that features the crusher feeds of most other porphyry properties. New Cornelia ore reaches the primary crushers with a greater. proportion of large 'pieces. When the New Cornelia company first equipped its 'property, it used the following machines and flow , scheme to reduce the ore to leaching size:

Jan 1, 1925

By H. Warlimont

In recent investigations of the microstructure and crystallographic features of martensite by electgon microscopy,', '9 thin films (about 50 to l000A in thickness) have been used as specimens. It was found by W. Pitschl ,2 that the lattice relationships between the supefiaturated fcc matrix and the martensite formed in thin films were different from those observed after transformation in bulk material. Corresponding differences are to be expected in nucleation and in reaction kinetics in the formation of martensite in thin films, but have not yet been reported. In the course of the preparation of thin films of iron-base alloys for investigation by electron microscopy it was observed that films of alloys, whose martensite formation temperature (Ms) was below room temperature, formed martensite during the electrochemical thinning process conducted at or above room temperature. The chemical compositions and approximate bulkM,-temperatures of the three materials on which this observation was made are listed in Table I. The alloys were vacuum-melted from high-purity metals. It can be seen that the effect occurred in alloys that contain only sub-stitutional components as well as in alloys that contain carbon as an interstitial solute. The appearance of martensite formed in this manner is illustrated in Fig. 1, which represents a polished film of alloy No. 1 at XI0 magnification. The martensite plates can be recognized by their surface relief effects. In addition, heavily strained (owrinkledo) austenite can be seen near the edges of the film where it is thinnest and transformation stresses or strains can be accommodated by plastic deformation most easily. The nonuniform distribution of transformed regions is probably due to the varying thickness of the film. These observations were common to all materials listed in Table I. Because effects of supercooling or straining can

Jan 1, 1962

By T. D. Guldem, J. L. Kaae

ALLOYS with nominal composition of 45-Fe 35-Ni 20-Cr, ASTM-B-163, known under the commercial names of Incoloy 800 and Sanicro 31 (Alloy 800), are often employed at elevated temperatures for extended periods. Therefore, knowledge of the aging behavior of these alloys is of considerable importance. Significant decreases in ductility and increases in yield strength have been observed in the 45-Fe 35-Ni 20-Cr alloys containing about 0.4 pct Ti and 0.4 pct A1 after long-term aging at 540" to 700"~."~ However, no direct evidence has been presented for precipitation phenomena that might result in such changes. Strengthening effects have been attributed to the effects of local or-dering.3 Since y' precipitation (Ni3A1, Ti) is known to occur in similar alloys which contain more titanium and aluminum,4-7 it was decided to explore the possibility that y' might precipitate in these alloys and might be responsible for the changes in mechanical properties on aging. This note reports some observations of two distict types of matrix precipitates made by means of transmission electron microscopy, in a 45-Fe 35-Ni 20-Cr alloy containing 0.31 pct Ti and 0.4 pct Al. The steel used in this investigation was obtained from the Sand-vik Steel Works; it is designated Sanicro-31 (Alloy 800). The chemical composition of the alloy is given in Table I. Aging of solution-treated material at 700" and 800°C for 130 and 100 hr, respectively, produced the matrix precipitates shown in Figs. l(a) and l(b). It is apparent from these micrographs that the precipitate particles occurred in the form of thin square plates parallel to the matrix cube planes. Extraction replication and selected-area electron diffraction showed that the precipitates were M23C6. Coherency strains, consistent with the semicoherent nature of small M23C6 precipitates,' were evident for certain imaging conditions. In addition to matrix precipitation, preferential precipitation of M23C6 on dislocations was common, as has been reported previously for austenitic stainless steels.'" Specimens aged for longer times (-300 hr) at 700°C exhibited a different type of coherent matrix precipitate in addition to the M23C6. An example is shown in Figs. 2(a) and 2(b). In addition to the few large M23C6 precipitates, small precipitates exhibiting strain contrastl0,ll are present. The "line of no contrast" of the strain field of a given precipitate lies along differ-

Jan 1, 1970

By E. W. Dewing

The solubility of A14C3 in cryolite melts has been determined by holding the melt with aluminum in a graphite crucible for 4 hr at temperature, quenching the crucible in water, and analyzing the frozen salt by CH4 evolution. The solubility is given by log(wt % Al4C3) = 1.298 -1.l74 (wt ratio NaF/AlF3) independent of temperature in the range 985" to 1080°C. Additions ofA1203, .NaCl, CaF2, or LiF up to 10 wt pct do not affect the solubility, provided that LiF and CaF2 are replaced by equivalent NaFin calculating the ratio. The variation with ratio can be accounted for quantitatively on the hypothesis that the Mechanism of solution is Al4C3 + 2AIF3 = 3Al2CF2 since the solubility varies as (aAIF3) 2/3; Mechanisms involving C", C2- , AlC- , A12C2+, and Al2CF+are re-jected. At ratios above 1.5 truces of c;- are also present. It was noticed some years ago in this laboratory that carbon specimens made cathodic in a cryolite bath decrease in diameter over a period of time.' It was also found that cryolite which had been melted with aluminum in a graphite crucible was sometimes yellow, and that A14C3 could be seen intimately embedded in the cryolite crystals. CH, could be recovered by acid attack. There was thus reason to believe that A14C3 had a genuine solubility in molten cryolite, and the object of this work was to measure it. EXPERIMENTAL AND RESULTS A graphite crucible, 2 in. ID and 2.5 in. deep with a close-fitting lid, contained about 150 g of cryolite (plus additives) and about 20 g of 99.99 pct pure Al. It was placed in a vertical Inconel furnace tube, covered with refractory brick to provide thermal insulation, and the top of the tube was roughly sealed with disks of asbestos paper. An alumina tube led argon down to the level of the top of the crucible to expel air, and an alumina sheath with a Pt-10 pct Rh ther-mocouple inside was positioned between the crucible and the wall of the Inconel tube. The tube was heated in an electrical resistance furnace for the desired length of time; the refractory bricks were then removed, and the crucible was lifted out with tongs and quenched in water. After such a crucible was broken open it could be seen that its inner surface was yellow owing to the presence of A1,C3, and sometimes needle-like crystals could be observed (at X75 magnification) growing out into the nielt. It was concluded that Al,C, had been present as a separate phase when the crucible was at tenlperature and that the melt had been saturated: in

Jan 1, 1970

By Louis R. Hodell

WHEN the drilling of an oil well is completed a permanent opening from the reservoir to the surface must be provided. This is done by lining the hole with pipe, commonly known as casing. In the past, all but a small amount of casing has been run in the hole and joined by threads and couplings. Recently, however, in California, Texas, and Oklahoma, there has been a definite tendency 'to adopt -the welded joint for the following reasons: (1) Plain end casing for welding may be bought for 15 per cent less than thread-and-coupled casing; some of this is offset by the cost of welding the pipe in the hole but a respectable net profit remains.

Jan 1, 1937

By P. E. Phillips

INTRODUCTION Rocky Mountain Energy is the mining subsidiary of the Union Pacific Corporation, and has been active m uranium exploration since 1966. Since 1970, RME's uranium activities have been funded 50% by Mono Power, the fuels supply division of Southern California Edision. RME and Mono recognized the need for development of new methods for recovering low grade uranium deposits, and contacted Halliburton Services in regard to in situ leaching, because of Halliburton oil industry experience. As a result, a joint venture between the three parties was formed in 1974. BEAR CREEK The first ISL test was at the Bear Creek deposit in the Powder River Basin of Wyoming, about 60 miles north of Douglas. The mineralized sand is the tertiary Wasatch formation, which is an arkosic sandstone. The sand typically contains about 10% clay. The predominant clay being montmorillonite with some kaolin and illite. The roll front type trends occur along the flanks of old stream channels. This deposit was being considered for exploitation as an open pit mine. Routine amenability testing indicated it was quite amenable to a conventional acid leach, consuming about 50 lbs. of sulfuric acid per ton of ore in an agitation leach, while recovering more than 95% of the uranium. Hydrology testing indicated a permeability of about 1 darcy. The groundwater has a pH of about 8. 0 and TDS of about 1200. Test Facility The Bear Creek test was a summer-only operation, with no effort towards weather-proofing. Uranium was removed from the recovered leach solution by fixed bed ion-exchange columns. Loaded resin was eluted with strong sulfuric acid. The recovery plant was designed for simplicity of operation, with little concern for the grade or form of the yellowcake product. The plant was constructed of PVC piping and valves, fiberglass reinforced tanks, and stainless steel pumps. All waste streams were directed toward a lined evaporation pond. Wellfield The test pattern was a 30 foot radius 5 spot, with wells fully penetrating the 30 foot ore sand to a total depth of about 165 feet. The injection wells were three-inch PVC with slotted casing, while the producer was eight-inch I. D. , with a stainless steel screen. The eight-inch well was necessary in order to accommodate a six-inch stainless steel pump. Wells were cemented using cement baskets, at the top of the sand, to contain a latex acid resistant cement. Leach Conditions The lixiviant generally contained from five to seven gpl sulfuric acid, and about 0. 5 gpl hydrogen peroxide. The pH was generally 1.4 and EMF was usually -550 millivolts. Injection rates were rather variable from well to well, with a total injection rate between 12 and 25 GPM. Production rate was set at 25 GPM, since the production pump could not be throttled more than that. Approximately two pore volumes of solution were injected during the three-month test. Leach Results Injectivity was quite variable, but was generally rather poor, because of poor completion techniques. The problem stemmed from injecting before the injection wells had been completely cleaned of drilling mud. Pregnant solutions averaged about 50 ppm U308, with groundwater dilution varying from 10 to 50%, depending on the injection rate. Injectivity did decline with time, probably as a result of contamination of the well faces. A total of 1000 lbs U308 had been recovered when the test was shut down. This probably represented about 10% of the mineral under leach.

Jan 1, 1979

By Amitava Gangulee, Michael B. Bever

The order-disorder transition in Ag-Mg alloys in the range 17 to 26 at. pct Mg was investigated and some thermodynamic, electrical and mechanical properties of ordered Ag-Mg alloys were measured. A modification of the phase diagram is proposed on the basis of measured transition temperatures. The stability of the ordered structure is analyzed in terms of the quasichemical theory. Kinetic aspects of the order-disorder transition were also investigated. The energies of ordering at 273°K of Ag-Mg alloys were measured by liquid metal solution calorimetry. The electrical resistivities and the tensile Properties of the ordered alloys were measured. The exothermic energy of ordering increased with magnesium concentration up to the composition Ag3Mg; it is discussed in terms of the quasichemical theory. Pronounced order hardening was observed and can be explained by several strengthening mechanisms, which are particularly effective because of a change in crystal structure associated with the ordering transition. IN silver-rich solid solutions containing approximately 17 to 26 at. pct Mg, long- range ordering may occur during appropriate therma1 treatments. Clare-brough and Nicholas1 first detected such long-range order in the solid solution of composition Ag3Mg and suggested that the unit cell of the superlattice contained 256 atoms. x-ray2 and electron diffraction3 investigations confirmed the occurrence of long-range order, but indicated a shifted Ll2-type structure. On the basis of recent X-ray measurements the crystal structure of ordered Ag3Mg has been confirmed as type D023.4 The present paper is concerned with the order-disorder transition in silver-rich Ag-Mg solid solutions and some thermodynamic, electrical, and mechanical properties of the ordered alloys. The effects of short-range order on the properties of silver-rich solid solutions containing up to 26 at. pct Mg are discussed in a concurrent paper.5 1) EXPERIMENTAL PROCEDURES 1.1) Preparation of Specimens. Specimens of Ag-Mg alloys containing from 18 to 26 at. pct Mg were prepared in the form of 1.0-mm-diam wires as described in Section 1.1 of Ref. 5. Disordered specimens were prepared by annealing at 773°K for 1 hr and quenching into iced brine. Ordered specimens were prepared by annealing at 773°K for 1 hr and slowly cooling to room temperature over a period of 15 days. The specimens were stored at 78°K. 1.2) Resistivity Measurements. Electrical resistivi- ties were measured by a potentiometric method.' Equilibrium values were obtained at several temperatures. The kinetics of ordering were investigated by following the time-dependent changes of the resistivity of initially disordered specimens during annealing. The specimens were enclosed in copper capsules and immersed in salt pots; the heating up was accelerated by injecting preheated helium into the capsules. 1.3) Calorimetry. The energies of ordering of the alloys were measured in a tin solution calorimeter as the difference between the heat effects of additions of completely ordered and disordered specimens of the same composition. The procedure and the method of calculation have been described.6 Magnesium was used for thermal compensation in most calorimetric runs in order to improve the accuracy.677 1.4) Mechanical Tests. Tensile tests were carried out with wire specimens at room temperature as described in Section 1.5 of Ref. 5. Microhardness measurements were also made.? 2) RESULTS AND DISCUSSION The characteristics of the order-disorder transition of silver-rich Ag-Mg solid solutions will be discussed first. Some thermodynamic, electrical, and mechanical properties of the ordered alloys will then be considered and compared with the corresponding properties of dis-disordered alloys. 2.1) The Order-Disorder Transition. 2.1.1) Thermodynamic and Structural Aspects. The transition temperatures Tt were determined from discontinuities in the slope of the equilibrium resistivity vs temperature curves. Normalized curves for three compositions are shown in Fig. 1. The transition temperature increases with the magnesium concentration and reaches a maximum at the stoichiometric composition Ag3Mg. The transition temperature of the alloy Ag3Mg was measured as 665° ± 2°K and compares with published values of 660°,1 663°,8 and 66°k.3 In the slopes of the resistivity vs temperature curves of alloys containing 22.2 and 22.5 at. pct Mg, discontinuities were observed at two temperatures. Such upper and lower discontinuities indicate a two-phase field. A modified form of the published phase diagram9 is shown in Fig. 2. A two-phase field was found only on the low-magnesium side of the composition Ag3Mg. On the high-magnesium side, the existence of a two-phase field could not be established because of insufficient resolution, but such a field must be present. This part of the phase diagram can be made complete by a eutec-toid-type reaction a = (a' + ß). The existence of a boundary between the two-phase fields (a + ß) and (a' + ß) is also in accord with published lattice parameters.3 The crystal structure of ordered Ag3Mg (type Do23)

Jan 1, 1969

By A. Gatti

Studies were made on the system iron plus alumina. Various methods of dispersing and various amounts of alumina were used. Powder metallurgy techniques were used to produce the final product. Microstructures and some mechanical properties are presented. Alloys containing up to 16 pct alumina by weight are ductile at all temperatures tested. The ivon-alumina materials have a higher yield stress and improved creep resistance over that of pure iron. SINCE the development of SAP' an A1- Al2O3 powder metallurgy product, great interest has been shown in the development of a SAP-like structure in metals and alloys other than aluminum. The outstanding properties of this class of materials are: 1) Good creep resistance at high temperature. 2) High yield strengths and high hardness at high temperatures. 3) High recrystallization temperature. However, the lack of ductility and formability has thus far limited the applications of SAP-like materials. The following report deals with methods of dispersing A12O3 in Fe, processing of powders into rod, structures produced after processing, and mechanical properties of the iron-alumina material produced. Methods of dispersing the alumina and also the volume fraction of alumina added were varied. MATERIAL Powder Processing— Four methods of obtaining dispersions of alumina in iron were studied. 1) Oxidation-reduction of a Fe + 8 pct Al alloy. .2) Coprecipitation of Fe(OH)3 + Al(OH)3 from aqueous solution. 3) Colloidal mixing of Fe,O3 and Al2O3. 4) Colloidal mixing of Fe powder and A1,O3. Fig. 1 is a processing flowsheet which outlines the processing steps taken to produce a final extruded bar 1/4 in. in diameter and about 30 in. long. The - 100 mesh iron-aluminum alloy was oxidized by placing a thin layer of powder on an alumina plaque. The reduction step was modified to include 1/2 hr at 1000°C since the powders tended to become pyro-phoric unless sintered slightly after low-temperature reduction. Compacting was done in a 1-1/8-in.-diam pressing die. The slugs produced averaged 1 in. in length. The billets were encased in low-carbon steel cans shown schematically in Fig. 2. The blank is included for structure and property comparison purposes. TESTING PROCEDURE All tests were made on as-extruded material.

Jan 1, 1960

PRESIDENT BENJAMIN B. THAYER,1 NEW YORK, N. Y. PAST PRESIDENTS JAMES F. KEMP,1 NEW YORK, N. Y. CHARLES F. RAND,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT SIDNEY J. JENNINGS,1 NEW YORK, N. Y. TREASURER GEORGE C. STONE,1 NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND, NEW YORK, N. Y.

Jan 4, 1914

By James E. Little

(Wilkes-Barre Meeting, June, 1911.) OF the several extensive deposits of brown iron-ore in Cuba, including those of Mayari and Moa, that of Mayari was the first to be systematically explored, and was selected as the scene of the first operations in the development of this class of ore. Construction-work, begun in the spring of 1907, involved the building of 16 miles of standard-gauge railroad and two large double-track inclines, the installation of mining-machinery, a nodulizing-plant, power-plant, shops and shipping-facilities, and the dredging of an extensive basin for deep-draught vessels. Unusual weather-conditions delayed the completion of portions of this work so that the entire plant was not in operation until December, 1909. The ore in its natural state contains a very large percentage of water, which increases to some extent with the depth below the surface. Near the surface it is red in color, with somewhat granular structure. The color gradually changes with depth, finally reaching a bright yellow. The consistency also changes towards, the bottom to a clay-like, sticky mass. The relative proportion of red and yellow ore is quite variable; in some places the yellow reaches close to the surface, while in others the red extends almost to the underlying serpentine. Fig. 1 is a map showing the Mayari division of the Spanish-American Iron Co. The ore lies on an irregular plateau about 15 miles long and 5 miles wide at the widest point, entirely covered with pine trees and brush, which grow directly on the ore. The elevation at the northern extremity, which is approached by the railroad, is about 1,700 ft. above sea-level. At the southern end the general elevation is about 2,000 ft. Ore is removed by means of scraper-bucket excavators and steam-shovels, these machines loading into special standard-guage, side-dump steel cars of 100,000 lb. capacity. A short haul

Aug 1, 1911

By L. R. Woodyatt, H. J. Beattie, C. T. Sims

Theories correlating the formation of u and related intermetallic compounds to the electron-per-atom density of binary and ternary alloys have appeared regularly in recent technical literature. These same principles can be modified and applied to complex precipitation-strengthened alloys such as the iron-, cobalt-, and nickel-base superalloys and the stainless steels. Since these complex alloys contain carbides and other phases that normally precipitate before the U-type phases, the nature and amount of the precipitated phases must be calculated first. The following general formula is then applied to the residual matrix composition of the alloy: element. The magnitude of the resulting number is indicative of whether the alloy will form a a -type phase. When these calculations (which are computerized) are systematically applied to alloys of knoun phase analysis, a breakoff in average electron-vacancy number is noted between U-free and U-prone alloys. Alloys with an average electron-vacancy number higher than the breakoff form a-type phases, while those with lower ones do not form these phases. This method could then be used to eliminate from consideration all experimental compositions that would precipitate undesirable phases. It also is useful in evaluating analyzed heats of alloys where minor heat-to-heat variations determine whether the alloy is o-free or o-prone. THE highly significant development of strong, ductile superalloys to provide reliable construction materials in the 1000" to 2500° F temperature range has been due principally to unremitting application of Edisonian techniques and logic by the dedicated physical metallurgists who have shouldered this responsibility. Tools such as the electron microscope, phase analysis, and computers to accomplish regression analyses have been used heavily, but the effort has been essentially practice of an art, rather than a science. The objective of this paper is to describe and illustrate application of some relatively fundamental principles to certain of these alloy systems in an attempt to remove some of the empiricism from the technology. Specifically, the work presented here deals with the use of periodic-group relationships to predict the formation of intermetallic phases which can occur in primarily austenitic (fcc) structures. Calculations that have been developed might be applied in the design of new alloys and the evaluation of known alloys, and thus have the potential of eliminating vast areas of unnecessary alloy preparation and evaluation. ALLOYING CONCEPTS AND STRUCTURAL FEATURES OF SUPERALLOYS Strength is produced in austenitic superalloys by three principle mechanisms: 1) precipitation of y'; 2) formation of carbides; 3) solid-solution hardening by soluble refractory metals. The first mechanism requires the addition of aluminum and titanium, the second requires carbon and carbide-forming elements, while the third calls for the addition of molybdenum and/or tungsten. A considerable concentration of chromium is usually maintained to resist oxidation/corrosion, but it is also an important carbide-forming element. Fig. 1 shows a sketch and electron micrograph of the structure of a typical wrought nickel-base super-

Jan 1, 1967