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By Edwin T. Myskowski, Alfred H. Hesse

The development by the U. S. Bureau of Mines of a process for purifying manganese by electrolysis has stimulated interest in manganese alloys. While recent publications have shown some alloys of manganese and copper to possess rather unusual properties, none have included information on tensile properties, which have an important bearing on the usefulness of the alloys. Manganese-copper alloys can be heat-treated, since the single phases that exist at high temperatures may be retained by quenching. According to Persson,1 when quenched alloys containing from about 30 to nearly IOO per cent manganese are reheated, alpha manganese is precipitated (Fig. I). Calculations based on Persson's X-ray data indicate that this decomposi-tion is accompanied by a change in volume of as much as ; per cent. The reason that this large volume change has not been noted probably is the slow rate at which equilibrium is reached by these alloys. In an investigation on hardening by cold-work and heat-treatment, Dean and Anderson3 found that quenched alloys increase in hardness with manganese content and that high-manganese alloys harden very slowly with cold-work, while high-copper alloys harden much more rapidly. Heat-treatment has little effect on manganese-copper alloys containing less than 40 per cent Mn, and affects those alloys containing more than 40 per cent in accordance with their manganese content and heat-treating temperature. Dean and Anderson4 also found that cold-work increased electrical resistance of alloys containing from 50 to 80 per cent Mn, and that heat-treatment of alloys containing from 40 to 96 per cent Mn altered the electrical resistance considerably. Dean, Anderson and Potter6 have shown that the high vibration damping capacity that characterizes manganese-copper alloys containing 40 to go per cent Mn is affected by cold-work and heat-treatments. Highest vibration damping capacity at low stresses was obtained by heating for 2 hr. at 450°C. (842°F.) after quenching from solution temperatures. Preparalion of Alloys.—The alloys for these tests were melted in a 17-lb. basic-lined high-frequency induction furnace using electrolytic manganese, grade A ingot copper and a 70-30 CU-Mn master alloy (69.80 per cent Cu, 0.12 Fe, 0.04 Si, 0.006 S, 0.07 C, balance Mn). The manganese was heated slowly to expel excess dissolved gases and melted before the addition of copper. No fluxes or covers were used. The melts were cast in tapered iron molds and the ingots were reduced go per cent when forged to 1/2-in. rounds. These rods were given 2-hr. solution treatments at temperatures that depended upon the composition (Table I). Tensile Tests.—The tensile specimens, 0.313-in. diameter (1.25-in. gauge length),

Jan 1, 1942

By D. R. de Fontaine

By computing the values of the resolved shear stress for a great many orientations of the tensile axis on all 12 (111) <110> slip systems, Taylor and Elam&apos; were able to map out a stereogram of slip systems, given here, Fig. 1, in Diehl&apos;s notation (see, for example Hauser and Jackson&apos;). The purpose of the present note is to derive such a stereogram by mathematical reasoning and to give a simple method of defining the system with highest resolved shear stress for any direction of the tensile axis, thereby eliminating tedious computation of the Schmid factor. Let the tensile axis, of direction cosines [xyz], make the angles 0 and relative to the slip plane normal [HKL] and the slip direction [hkl] respectively. Fig. 2 shows a simple cubic cell whose edges define a Cartesian coordinate system. Let A be a unit vector of origin 0 supported by the tensile axis. Its end point [xyz] then lies on a sphere of unit radius, on the positive hemisphere of which the planes z = 0, x = y, y = z limit the so called primitive triangle of a standard [loo] stereographic projection. For any point of this triangle, the following hold: 0«2 «y *sx « 1 [l] Now, for given [xpz], the most highly stressed system will be the one for which the following expression of the Schmid factor has the largest possible value: (HKL) belonging to the form (111) and [hkl] to the form <110>, the denominator on the right hand side of Eq. [2] is equal to 1.fi.a. The unknowns H, ... h, . . . can now be determined by correctly distributing +1 and -1 to H, K, L, and +1, -1,O to h,k, 1 giving the numerator of Eq. [2] its greatest positive value (the angles 0 and cpare chosen acute) subject to the condition: Hh+Kk+Ll = 0 [3] since the slip direction must lie in the slip plane. Condition [3] can be satisfied only by having one of its terms vanish and the other two equal to +1 and -1. Taking the case of the tensile axis lying in the primitive triangle, x2y, z and therefore Hh will be chosen equal to +1 with H = h = +1 in order to retain a maximum of + signs. There remain two alternatives: either 1 = 0 or k = 0. 1) take 2 = 0 Then Kk = -1 and the numerator of [2] becomes: Retaining a maximum of + signs gives L = k = +1 and becomes: 2) take k = 0 Then L1 = -1and, likewise, the numerator of [2] becomes: xz - z2 + xy + yz [5] But the difference [5] - [4] can be written: (y - z)(x+y +z) [6] positive or zero by virtue of [I]. If [6] is positive (y > z), then the largest possible value for the numerator of [2] for any xyz inside the primitive triangle is given by [5], i.e., for: That is to say, the active slip system corresponding to an orientat:~on of the tensile axis inside the primitive triangle is:

Jan 1, 1962

Phase II of President Nixon&apos;s economic game plan will incorporate many top flight metals mining companies. The large corporations must receive approval from the Cost of Living Council before increasing prices and or wages. The theory here is that, with large companies complying with advance approval, smaller firms will be examined more closely by government, and thus will be forced also to comply. Rep. Paul McCloskey (R.-Calif.) called for a moratorium on strip mining for "the few years involved before we adopt a national energy policy and a national land use policy." McCloskey, who is a cosponsor of Congressional legislation that would outlaw strip mining, told a hearing that a "moratorium can scarcely hurt us until national energy and land use policies are adopted."

Jan 1, 1971

By R. I. Jaffee, H. R. Ogden, D. J. Maykuth

Phase diagrams for the Ti-W and Ti-Ta systems were determined. The Ti-W system is characterized by a wide, two-phase region of ß plus tungsten which is derived from a peritectic reaction between the liquid and tungsten solid solutions. The ß field terminates in a eutectoid reaction between a titanium and tungsten terminal solid solution. Tantalum and ß titanium form a complete series of solid solutions. Other features of this system are the extensive a-ß field at low temperatures and an appreciable solubility of tantalum in a titanium. BOTH tungsten and tantalum were first thought to form ß-isomorphous systems with titanium as a result of early work&apos; using powder-metallurgical techniques. Later work2 on arc-melted Ti-Ta alloys, made using a commercial titanium base, showed that, in the range of 0 to 10 pct, tantalum was soluble in ß titanium and that the a solubility extended to between 2 and 5 pct Ta at 790 °C. The present investigation covered the entire alloy range in both systems and was chiefly concerned with high-purity alloys at the titanium-rich end. The constitution of titanium-rich alloys made with a commercial titanium base was reported by Holla-day, Kura, and Jackson.3, 4 As will be shown in detail later, the early prediction of a isomorphism was true for the case of the Ti-Ta system, but not for the Ti-W system. The results of this investigation will be presented first. The experimental methods used are described in the Appendix. Ti-W System The entire Ti-W phase diagram is shown in Fig. 1. Details of the titanium-rich side are shown in Fig. 2. The chief features of the system are a ß eutectoid and a high-temperature peritectic between liquid and tungsten solid solution. Melting Range: Examination of cast structures of low and medium-tungsten-content ingots showed cored ß phase as the primary constituent. Fig. 3a illustrates a typical cast structure for alloys in the range of 20 to 30 pct W. From 30 to 72 pct W, coring was very severe. Alloys containing 72 through 88 pct W, however, showed definite evidence of a peritectic reaction between the liquid and a terminal solid solution of titanium in tungsten. Fig. 3b shows the cast structure for an 80 pct W alloy. A 95 pct W alloy, shown in Fig. 4, consisted primarily of primary tungsten solid solution plus a small quantity of ß probably rejected during cooling. Incipient-melting experiments located the peritectic temperature between 1850" and 1900°C and indicated that the reacting phases are liquid containing about 25 pct W and tungsten terminal solid solution containing about 8 pct Ti. Figs. 5 and 6

Jan 1, 1954

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.&apos; 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 J. V. Emmons

IT has long been known that the outside skin of tool steel frequently exhibits properties widely different from the interior of the mass. Within the last few years it has been generally recognized that many of these properties were clue to surface decarbonization. The origin and effects of this altering of the composition have been but little studied. C. M. Johnson&apos; arrives at the conclusion that, in annealing, "the most active agent in surface decarbonization is the rust or scale (present on the surface), which is actually reduced to metal at the expense of the carbon in the steel to which it adheres." W. H. Hatfield in his admirable paper, The Chemical Physics Involved in the Decarburization of Iron-Carbon Alloys,&apos; has given us the most tenable theory of the removal of carbon from iron. While Mr. Hatfield&apos;s work has been principally clone in connection with the annealing of white cast iron to produce malleable castings, it is frequently applicable to the decarbonization of tool steel. The following equations which he proposed have been fully borne out by the author&apos;s experiments: 2Fe3C + 2CO2 = 3Fe2 + 4C0 2C0 + 02 = 2C02 Continuous 2C02 + 2Fe3C = 3Fe2 + 4C0 It is the purpose of the author to show, in a quantitative manner, the effect of various treatments in eliminating the carbon in tool steel. Some of the phenomena of the decarbonized surface will also be described, as well as the practical problems they present to. the manufacturer and user of tool-steel products.

Jan 9, 1914

By Henry Knox

AMIDST the tumult and the shouting of the times, there are perceptible certain tendencies, quiet though serious, to take stock of the situation with a view to putting our house in order, and of these none is more encouraging than the awakening, interest in the higher education, and especially in technical education. Various committees of the professional organizations have cast much light on the matter and have pointed the way to progress and reform, but their scope is necessarily restricted by the requirements of precision and any excursion beyond these bounds must be undertaken by the unfettered individual who is free to rush in where responsible committees fear to tread. A discussion of the bearing of the higher education on character scarcely lends itself to objective treatment and yet, fraught as it is with imponderables and abstractions, the theme cannot be escaped in any com-prehensive scheme of education. The question is being pressed with growing insist-ence, why these United States, relatively to Europe, are deficient in intellectual output, and the ready reply, "Because America is a new country and Americans are too intent on developing their natural resources," is too facile and too false to carry conviction.

Jan 12, 1922

By Frank C. Greene

Drilling in Missouri in 1943 continued at a lower rate than in 1942, only 28 wells being completed. Following the completion of the Cities Service Oil Company&apos;s No. I Jim Cook near Tarkio, in the northwest corner, NW. &apos;fi sec. 32, T. 65 N., R. 39, W., Atchison County, four dry holes were drilled by other parties, all a mile or more from the Cook well. Later the Cities Service Oil Co, completed No. 2 Cook for 60 bbl. Table I gives a summary of activities by counties. The total footage drilled was 23,83134 ft., of which 12,802 1/2 ft. was by cable tools and 11,029 by rotary. Four of the dry holes were drilled into Mississippian or older beds.

Jan 1, 1944

By Frank C. Greene

Drilling in Missouri in 1943 continued at a lower rate than in 1942, only 28 wells being completed. Following the completion of the Cities Service Oil Company&apos;s No. I Jim Cook near Tarkio, in the northwest corner, NW. &apos;fi sec. 32, T. 65 N., R. 39, W., Atchison County, four dry holes were drilled by other parties, all a mile or more from the Cook well. Later the Cities Service Oil Co, completed No. 2 Cook for 60 bbl. Table I gives a summary of activities by counties. The total footage drilled was 23,83134 ft., of which 12,802 1/2 ft. was by cable tools and 11,029 by rotary. Four of the dry holes were drilled into Mississippian or older beds.

Jan 1, 1944

By K. S. Krishnam, A. G. Guy

VOLUME 6 of the Transactions of the Baikov Institute of Metallurgy, Moscow, is devoted to the subject of "the experimental and theoretical study of the physical characteristics of dilute solid solutions,11 and summarizes work that has been done largely in the years 1958-9. In view of the attention that Soviet investigators have given to this subject, it seemed useful to carry out an independent experimental investigation in an effort to judge the scientific basis and practical significance of this field of study. The present note is a preliminary report of this investigation. The first property studied by the Soviet group was X-ray spectra of solid-solution alloys.&apos; An anomaly observed at low concentrations (--0.05 at. pct) of the alloying element led to the theory that each impurity atom in a transition-metal base alloy is the center of a "block" of affected atoms with a radius of about 10"7 cm. This theory was further developed in a later paper.2 By this time similar anomalies had been found in diffusion coefficients3 and in thermal expansion.4 The entire development up to 1959 was reviewed in a comprehensive paper, and further theoretical ideas were also published at this time. Finally, the volume mentioned above was published in 19607 giving new experimental data on anomalies in optical properties and Hall constant, and a new theoretical treatment also appeared.&apos; Although western scientists have done both theoretical work, summarized recently by Friedel,9 and considerable experimental work on dilute solid solutions, there is little support for the marked anomalies reported in the Soviet papers. Of the physical properties studied by the Soviet investigators, thermal expansion was chosen for the present investigation because of the relative ease of obtaining the necessary precision of measurement. A Leitz dilatometer was used for this purpose, and a special technique involving interchanging of the two specimens being compared permitted a precision of 0.05 x X in average thermal expansion over the range 27° to 600°C. The specimens were heated and cooled in vacuum or in a protective atmosphere at a rate of 50 °C per hr. Ferrovac E iron was used as the comparison specimen and in every case had a coefficient of expansion higher than (or equal to) that of the alloy. Since unintentional impurities are an important factor in studies of dilute alloys, special attention was given to the purity of the iron and the alloys used. The alloys were the same of those used by Abrahamson10 and by Michalak," and their preparation is described in these references. Chemical analyses of the Ferrovac E iron and of typical Fe-W and Fe-Mo alloys are given in Table I. The purity of the iron and alloys is undoubtedly higher than in the

Jan 1, 1962

By B. W. Frazier

At a recent meeting of the North of England Institute of Min ing and Mechanical Engineers, during a discussion upon the com pression of air, attention was called to an apparent anomaly in the phenomena attending the compression. At a subsequent meeting this apparent anomaly was explained by Prof. Herschel, and all the facts observed shown to be strictly in accordance with the laws of thermodynamics. Upon reading the report of the discussion in the published transactions of the society, it occurred to me that an attempt to determine mathematically the amounts of energy (whether in the form of heat or of work) expended and absorbed in compressing air, and causing it to perform work by expansion, might prove of use to some who have not access to any treatise upon the application of the laws of thermodynamics to the compression of air, and who have not the time or the inclination to make such application for themselves. The apparent anomaly noticed was this: If air be compressed, and at the same time, by the sufficient application of a cooling medium, kept at a constant temperature, the indicator diagrams in the

By I. R. Dunlap, R. F. Burdyn, F. D. Patchen

The composition and properties of a new type of cementing mixture are discussed. In these compositions, API Class A or C cements are added to n stable water-in-oil emulsion instead of the crsual water. The cement disperses in the oil phase and remains out of contact with the water under normal conditions of mixing and storage. At higher temperatcrres, such as those encountered down-hole during placement, the emulsion breaks and cement hydration can then proceed. An extremely low filtration rate is obtained; the major part of the filtrate is oil. Thickening times of the mixture may be increased to meet the 18,000-ft casing cementing schedule by varying the amount of emzilsifier. As in conventional Portland cement mixtures, high-temperature strength retrogression can be overcome by addition of silica flour. Results of several field app1ication.r show that mixing presents no diffculty if emulsion blenders are used and the emulsion is prepared beforehand. INTRODUCTION Water-in-oil emulsions., in which oil is the continuous or external phase and in which water exists as discrete droplets, have for some time been used successfully in drilling muds to reduce filtration loss.1,2 Applied to cement slurries, the same results are obtained; i. e., the fluid-loss is greatly reduced. In addition, thickening times may be extended, lower densities and strengths obtained, and water-base borehole fluids more easily displaced without contamination of the cement. A low filtration rate is often a desirable property in oil well cements since loss of fluid increases placement difficulties and may also cause damage to water-sensitive producing formations.&apos; In the casing cementing operation where the cement slurry is pumped into the narrow annulus between open hole and casing, rapid loss of fluid to a porous formation can cause the slurry to thicken and plug the annulus before the desired fill is obtained. Where a casing or a liner is cemented against a productive formation and the well completed through perforations, the fluid lost between the time the cement first contacts the formation and the time a set is obtained may invade the zone past the depth of the perforations. If the sand contains a material which will swell upon contact with cement filtrate, permanent damage may result. Previous methods for reducing the fluid-loss of cements have employed bentonite4 as an additive, usually with a lignosulfonate as a dispersant, or a derivative of some naturally occurring polymeric material such as cellulose ether." Oil emulsion cements have also been proposedv or fluid-loss reduction, but these have been of the oil-in-water type. Bentonite cements have been used most widely and have been successful in reducing incidence of premature setting of cement attributable to loss of water by filtration. It is the purpose of this paper to describe preparation and properties of a water-in-oil emulsion cement and to relate procedures followed and results obtained in several field applications. DESCRIPTION OF SYSTEM AND MECHANISMS A water-in-oil emulsion cement is prepared by adding an API Class A or C cement to a stable water-in-oil emulsion. Fig. 1 is a photomicrograph of this emulsion before addition of cement. Here the droplets are water and the surrounding medium is diesel oil. High emulsion stability is indicated by the small droplet size [1-5 microns], and by their uniformity.&apos; To form a stable water-in-oil emulsion as illustrated, several conditions must be met. A predominantly hydrophobic emulsifier must be present in sufficient concentration to produce a strong interfacial film; initially, the phase volume ratio (the water-to-oil ratio) must be low;

By Charles H. Moore

In the study of the properties of rutile pigments it became apparent several years ago that certain physical and optical properties could not be determined on particles of pigmentary size. Since reflected light is the dominant type which reaches the eye from small particles, the true color of pure rutile was not known. Most rutile pig-ments are acicular in habit, elongated parallel to the "c" axis. It was considered important to know the nature and tone of light transmitted, for example, by a basal plate. Further, as shown by spectrophotometric curves, there is a very strong absorption of light of 4000 A as measured on particles with random orientation. It would be interesting to see whether this absorption position varied with predetermined and selected orientations. Also, since the behavior of titanium pigments in a vehicle is important, a knowledge of the surface wettability of single crystals by various media should prove very fruitful. Finally, the optical properties of rutile are such that it should show, in a single pure crystal, greater fire and brilliance than the diamond. Mineralogists had long speculated that this would be the case and curiosity was strong to produce a single crystal large enough to cut. In light of the above, a project was initiated for the formation of single crystals of rutile. Method of Formation of Rutile Single Crystals Fortunately, purification of TiO2 produced from both titanium tetra-chloride and titanyl sulphate solutions had reached the stage where spectro-graphically pure starting material could be made. Spectrographic analysis of the feed material used in the initial experiments is compared with the present feed material in Table 1. It is apparent that the present large scale purification is approximately as good as the original experimental, small scale purification. Verneuil1 produced synthetic ruby and corundum in 1904 by the well-known flame fusion process, which today bears his name. Except for mechanical improvements the present commercial production of synthetics by flame fusion is essentially unchanged from his initial method. His burner consisted of an inner orifice through which was fed the feed material and oxygen. Surrounding this was a larger outer orifice through which was fed hydrogen at lower pressure. This arrangement consists then of a lance of oxygen burning in an atmosphere of hydrogen. The proportions of hydrogen to oxygen usually used in corundum production is about 3:1, providing there is sufficient temperature to reach the 2050.°C required for the fusion of alumina. From work done in the Titanium Division Laboratories2 and from the published work of Erlich3 it was known that rutile appears to lose oxygen near its melting point and that it would not be possible to grow single crystals in a strongly reducing environment. Consequently, in order to determine whether single crystals could be grown at all, an Airco oxygen-acetylene torch with

Jan 1, 1950

By J. H. O’Dette

BLISTER formation on wrought aluminum products has been a matter of concern to aluminum fabricators for many years. The fact that blisters make their appearance during the final stages of fabrication means that much time and effort have been expended before it is evident that the material must be scrapped. This and the loss of production are ample reasons for embarking on a research program to find out more about blistering and possible methods of control. Many excellent papers on this subject have appeared in the technical literature in the last few years. In one of the more recent papers, Kostronl gives a fairly complete review of the problem of gas in aluminum and blistering in general. From the work of the various investigators, a general mechanism for the formation of blisters has evolved and may be summarized briefly as follows: Hydrogen gas is usually present in the cast ingot, in the atomic or ionic state, in excess of the solid solubility. At room temperature the gas atoms are relatively immobile, but at elevated temperatures they become mobile and diffuse to free surfaces where they associate to form molecules. If these free surfaces are discontinuities within the ingot then the associated gas molecules collect and build up considerable pressure until equilibrium is reached with the dissolved gas around the discontinuity. Since the solubility of the gas is proportional to the square root of the partial pressure it is evident that large pressures may be built up at the discontinuities. When the metal is rolled to sheet the pressure of the gas in these, discontinuities is sufficient to deform the surface of the sheet and form a blister, particularly when the strength of the material is reduced during the annealing. Although the mechanism of the formation of blisters was fairly well known, the actual impor- tance of the individual roles played by the gas and the discontinuities was not so well established that positive methods for control of blistering were at hand. It was the object of the investigation to learn more about the nature of the discontinuities giving rise to blistering and to develop methods of control. The investigation was carried out in three stages as follows: a) A study of the more commonly used methods of removing hydrogen from aluminum, such as fluxing and holding, and their effects on blistering. b) Location of the discontinuities giving rise to blistering. c) A study, by indirect methods, of the movement of gas in the metal and its effect on blistering, and the development of methods of blister control during fabrication. Removing Gas and Reducing Blistering by Fluxing or Holding-—The work of removing gas and reducing blistering by fluxing or holding was carried out on metal of Alcan 2s (1100) composition with an artificially high gas content. The high gas content was obtained by introducing water into the melt prior to casting; the water reacted with the aluminum forming A12O3 and hydrogen. The procedure was to raise the gas content by introducing water into an aluminum melt and using half the melt to cast one ingot immediately. The remaining metal was treated again with water to make up for the reduction in gas content during holding, while the first ingot was being cast, and then given a fluxing or holding treatment and cast into an ingot. Samples for gas determination were cast from the molten metal before and after the gassing operation; before, after, and during fluxing, and while casting. Samples were also cut from sections of the ingots. Gas determinations were made on these samples using the well known vacuum fusion technique. All ingots were hot rolled at 500°C to 0.250-in. slab which, in turn, was cold rolled to 0.040 in. sheet. The sheet was coiled and annealed for 2 hr at 500 °C and then cut into 5-in. squares which were inspected for

Jan 1, 1958

By F. A. Crossley

The additions: o, Sn, Zr, Cb, Mo, and V were studied for their effects on the a/a + Ti3A1 boundary of Ti-A1 base ternary alloys. These additions were chosen because of their importance to commercial titanium alloy practice—oxygen as the major impurity (in terms of influence on mechanical properties) and the others as major alloying additions. The composition and temperature ranges of investigation varied according to the system as shown in Table I. The principal means of investigation was light-microscopy. The basis of the ternary studies was the recently determined titanium-rich end of the Ti-A1 system.&apos; MATERIALS, METHODS, AND PROCEDURES Ingots were prepared in 15 g size for all alloys except those of the Ti-Al-Mo and Ti-A1-V systems which were prepared in 20 g size. These alloys were prepared from high-purity, electrolytically refined titanium obtained from the Bureau of Mines, Boulder City Metallurgical Laboratory, Boulder City, Col., and Chicago Development Corp., Riverdale, Md., for the 15 g and 20 g ingots, respectively. The alloying additions were obtained from commercial sources, and were at least of 99.9 pct purity, except the V-15 wt pct A1 master alloy for vanadium additions. This alloy was of 98.2 pct purity; the major impurities were 0.37 wt pct Fe and 0.38 wt pct Si. The ingots were prepared by multiple melting in a nonconsum-able-electrode arc furnace. The ingots were covered with Markal coating "CR-T22" (Markal Co., Chicago) to protect them from scaling. Markal coating is applied as a slurry of solids in a volatile carrier liquid. The coated article is air dried. Upon heating to the hot working temperature the coating fuses to form a glassy, protective film. The ingots were heated to 1000°C and rolled to 0.16 in. thickness, reheating after each pass. The glassy film was removed by sand blasting. Ten mils were removed from all surfaces by grinding and/or pickling (3 pct HF, 30 pct HN03, balance water). Grinding was always followed by pickling to remove traces of the grindmg medium. Hydrogen removal was accomplished by vacuum annealing at 1000°C for 2 hr to a final pressure of about 0.02 µ Hg. This was followed by annealing in evacuated Vycor bulbs (800°C, 2 hr, ice brine quenched (IBQ)) in order to maximize ductility. The materials were then lightly pickled and cold rolled to 0.12 in. thickness or cracking, whichever occurred first. After rolling, 1/2 by 1/4 in. specimens were cut for the equilibration anneals given in Table 11 and carried out as previously described.1 Final polishing of the specimens for metallographic examination was done by electrolytic means. Specimens were first examined without etching under bright field and polarized light illumination, for this is the only means of detecting the "two-phase" phenomenon.1,2 The term "two-phase syndrome" refers to Ti-A1 al-loys which appear on the bases of their chemical, phys-ical, and mechanical properties, to be two-phase, but are actually single phase and inhomogeneous in composition. Since processing and heat treatment of the alloys of the first group were completed before the two-phase syndrome was discovered, a number of the specimens were found to exhibit this phenomenon—80 pct of those of the Ti-Al-Zr system, 5 pct of those of the Ti-Al-Sn system, 30 pct of those of the Ti-Al-Zr system. The affected specimens were homogenized by heating above the ß transus temperature and quenching. The heat treatment and working schedules to accomplish this are given in Table 111. After rolling, specimens were pickled (3 pctHF, 30 pct HNO3 in water) to remove 1 to 2 mils from the

Jan 1, 1970

By C. G. Dunn

This note describes a method for revealing micro-structures in tantalum through an {hkl} effect which was found during a study involving amorphous and crystalline tantalum oxides. Three steps are involved. First, an amorphous film of Ta2O5 is formed anodically1 on the surfaces of the tantalum. The amount needed depents on the thickness of the substrate tantalum; 1600Å of oxide, however, is generally satisfactory in the 1/2 -mil (12 µ) to 3-mil thickness range. The film at this point is uniform in color. Second, the anodized specimen is heated to 800°C in. vacuo during a period of a few minutes and held at temperature for 5 min. During such a treatment some oxygen leaves the oxide through dissolution into the substrate tantalum (e.g., at 10-8 Torr oxide films thinner than about 800 completely disappear on 5-mil strip). Considerable crystallization of the amorphous oxide also occurs adjacent to the metal/oxide interface but not throughout the oxide thickness. The thickness of oxide needed as a residue is not too critical; values between 500 and 1000Å (optical estimate&apos;) may be most useful. (The presence of a residual oxide layer after the heat treatment usually is not apparent; in fact, in most instances the surfaces have a metallic appearance. This can be the case also for thicker residual films needed in the detection of a crystalline oxide phase by surface X-ray diffraction—e.g., if the initial oxide film is 3000Å thick, enough crystalline oxide is formed for X-ray detection.) The third step eliminates the metallic appearance at the surface and reveals (or produces) a varied colored film of tantalum oxide. Two methods can be used and both will be illustrated. If the specimen is dipped in 48 pct HF for a few seconds, the tantalum is found to be covered with a multicolored oxide. Moreover the colors correlate with the grain structure of the substrate tantalum through an orientation dependence of the type illustrated in Fig. 1, where results of an orientation analysis by the Laue X-ray method have been plotted. Other film conditions would have provided a different set of colors for the same orientations. Any such correlation, however, provides a basis for a qualitative assessment of the distribution of orientations in a large sample. The cold-rolled structure of tantalum foil produced by a recrystallization anneal and a cold-rolling reduction of 95 pct is not easily obtained by usual metal-lographic methods.&apos; The structure, however, is easily revealed by the present technique, Fig. 2. The alternative third step is to reanodize the specimen. The optical nature of the final anodic film depends on the presence of the crystalline oxide phase; color variations indicate optical thickness variations in the film. As the reanodization voltage is increased from zero, straw and light brown colors appear (as usual), followed now by variations in color from grain to grain depending on {hkl} orientation. Suitable end points, which are determined by voltage and time, are easily established. Fig. 3, for example, shows the grain structure developed in 5-mil tantalum strip during a 30-min re-crystallization and grap-growth anneal at 1800°C. An anodic film of 1600Å thickness was added prior to the special 800°C anneal. Reanodization was done at constant current density (near 0.2 ma per sq cm) in an aqueous solution of H3PO4 (0.01 pct) and was terminated after the initial brown colors were replaced by a deep blue at approximately 30 v. Although good grain contrast can be obtained with bright field illumination, even greater contrast for black and white micrographs may be obtained with polarized light, as in Fig. 3.

Jan 1, 1967

By J. H. Hamilton, J. R. Lewis, J. H. Dismant, W. M. Fassell

RECENTLY this laboratory undertook the task of preparing some low carbon metallic cobalt by the carbon reduction of precipitated cobalt oxides. The oxides came in two lots and had the compositions given in Table I. Industrially, cobalt rondels&apos; are made by the carbon reduction of cobalt oxide in small reverberatory furnaces at temperatures near but not above 1050 °C. This is a slow and tedious small batch process but does give cobalt metal which is low in carbon (1 pct C). Inasmuch as these cobalt oxides were relatively low in copper and iron it was decided to reduce them with petroleum carbon in a small three-phase electric arc furnace of about 3 to 5 Ib of metal capacity. It was hoped such a procedure would save considerable time and perhaps also indicate an improved commercially feasible process. The furnace was preheated by using small pieces of carbon electrodes to maintain the arc until a temperature of 1500°C was reached. The broken pieces of electrodes were then removed and 500 g of the cobalt oxides and 60 to 100 g of petroleum coke added. At the end of the reduction reaction, a high lime flux was added to the furnace to facilitate the removal of sulphur. Due to the fineness of the cobalt oxide powder used and also to the presence of chlorides there was considerable dust lost in charging the furnace. This was overcome by preparing briquettes composed of the cobalt oxides, charcoal, and a little bentonite to serve as a binder. The results obtained are summarized in Table 11, which shows that the cobalt metal produced in the arc furnace was high in carbon varying from 2.5 to 3.5 pct. This, of course, is much too high. For certain uses, such as in the preparation of permanent magnets, the carbon content of cobalt must be low. It was necessary therefore to find an effective method of reducing the carbon content of the cobalt that had been prepared in the arc furnace. Van Arkel3 recommends the use of Co2O3 as a means of removing carbon from cobalt. Experiments by the authors indicate that carbon is removed with difficulty by this method. Other methods used, including lancing of the molten high carbon cobalt with a jet of oxygen, proved to be ineffective. The method finally used makes use of the fact that cobalt metal is decarburized by carbon dioxide at the temperature of the molten metal. Two methods were used: 1—carbon dioxide was bubbled up through the molten cobalt, and 2— molten cobalt was maintained in a carbon dioxide atmosphere. In the first method the gas was introduced below the surface of the molten metal by means of a quartz tube. A high frequency induction furnace was used to keep the cobalt molten in both of these experiments. This kept the metal somewhat agitated and no doubt was an important factor in hastening the decarburization &apos;process by the second method. Both methods gave satisfactory results as shown in Table 111. An interesting observation in connection with this &apos;work was that a small sample of carburized cobalt metal could be decarburized by heating it with an acetylene torch adjusted to give an oxidizing flame. This may have been due to the presence of carbon dioxide in the products of combustion. Samples of molten high carbon steel were decarburized by the same method and it is suggested that nickel and perhaps manganese can be decarburized in a similar manner. Additional work, including rate studies and other theoretical aspects of this problem, is in progress in this laboratory.

Jan 1, 1953

By R. W. Gurry

IN the course of a series of measurements of the rate of diffusion of carbon in austenite at about 960°C. (1760°F.) and 1110°C. (2030°F.), it became necessary to determine carbon concentration when austenite is saturated with graphite, because of indications that the hitherto accepted value of the solubility of graphite in this temperature range is too low. Specimens of carbonyl iron were saturated at temperature in a hydrogen-toluene atmosphere which was in equilibrium with graphite. The carbon content of the steel was measured either by combustion or by the loss of weight after substantially complete decarburization in an atmosphere of hydrogen saturated at room temperature with water vapor. The absence of carbide or graphite as a phase at temperature was demonstrated by microscopic examination of saturated specimens that had been drastically quenched. The mean result of concordant measurements is that gamma iron saturated with respect to graphite contains 1.39 per cent carbon at 957°C. (1755°F.) and 1.89 per cent at 1110°C. (2030°°F.). These two values, plotted along with what appears from the literature to be the best value (0.69 per cent) at the iron-graphite eutectoid temperature (738°C. or 1360°F.), yield a curve that is almost linear, and which, continued upward through a short interval, leads to a limiting solubility of 1.98 per cent at the iron-graphite eutectic temperature1135°C. (2095°F.) instead of the commonly accepted value of about 1.7 per cent. EXPERIMENTAL PROCEDURE The samples of carbonyl iron, with the exception of those for microscopic examination, were cylinders 3.8 cm. long, 0.475 cm. in diameter. They were placed in a graphite holder and suspended in a vertical furnace, the temperature of which was controlled precisely by means of the resistance of the platinum winding.1 In the empty furnace the range of temperature over a distance of 4 cm, at the heat center was 9°C. (16°F.) but at a given location the temperature remained within ±0.5°C. (0.9°F.); it was measured by inserting a platinum-rhodium couple calibrated at the melting point of palladium, 1555°C. Since the presence of the sample probably improved the uniformity of temperature, it was decided to consider the average temperature of the sample to be 3°C. lower than the maximum measured in the empty furnace with the same setting of the controller. Data were obtained in the vicinity of two temperatures, 960°C. (1760°F.) and 1110°C. (2030°F.). The samples for microscopic examination, 2.2 cm. long, 0.475 cm. in diameter, were suspended individually on pure iron wire; for these no temperature correction was applied. The carburizing gas passed into the furnace was dry, oxygen-free hydrogen saturated at room temperature with

Jan 1, 1942

By William Klement

THIS note reports the results of some attempts to metastably extend the primary solid solubilities of tin, antimony, and silicon in silver by rapidly quenching these binary alloys from the melt. The procedures employed for alloy preparation, quenching, and Debye-Scherrer X-ray diffraction measurements have been described elsewhere. The lattice parameters obtained for the fcc structures in Ag-Sn and Ag-Sb alloys are presented in Fig. 1, together with the results of Owen and Roberts.4 Alloy compositions are believed to be within ± 0.2 at. pct on the basis of negligible weight losses during preparation and reproducibility of the lattice spacings. Diffraction lines from hcp phases were also detected: the relative visual intensities of the fcc (200) and hcp (10.2) lines were estimated as shown in Table I. The intensities were m for the (200) and w for the (10.2) in a quenched 13.6 at. pct Sn alloy: a lattice spacing for the fcc structure could not be reliably obtained, however. As seen from Fig. 1, the lattice parameters vary linearly with composition up to 8., at. pct Sb and 13." at. pct Sn, respectively, which may be compared with the maximum equilibrium solid solubilities5 of 7.2 at. pct Sb and 11.5 at. pct Sn, respectively. The presence of the hcp phases, which were found together with the fcc phases, is a consequence of the competition1,3 in the nucleation and growth processes during solidification. Both the fcc and hcp phases must be of the same composition for those alloys in the range where lattice parameters increase linearly with solute concentration. Despite much effort with quenched alloys of several silicon concentrations, it has not been possible to obtain lattice spacings of sufficient precision to establish the variation of lattice parameter with composition or the maximum metastable solid solubility: the equilibrium data5 suggest little primary solid solubility of silicon in silver. For alloys containing less than 16 at. pct Si, the Si (111) diffraction line was not observed. For alloys containing 10 to 25 at. pct Si, faint low-angle lines were detected and these could be indexed as the (10.0), (00.2). and (10.1) reflections of an hcp structure with a = 2.87 + 3A. c = 4.52 ± 3A, and c/a = 1.57 ± 2. The 16 at. pct Si alloy was quenched to, and examined at. liquid nitrogen temperatures without any change observed in the proportion of the hcp phase. These experiments were jointly supported by the Atomic Energy Commission and Office of Naval Research under a program directed by Professor P. Duwez. The assistance of H.-L. Luo and A. Abu-Shumays is acknowledged. as is the support afforded

Jan 1, 1965

By G. H. BUCHANAN

ALTHOUGH the nomenclature of the chemical tools of flotation is probably familiar to you, it will do no harm to review it; . In order to make the terms more real I have employed an illustration which likens flotation to an old-fashioned balloon ascension, such as we witnessed in boyhood at the county fair. The mineral to be floated is the aeronaut, conspicuous in his gilt-spangled tights, who is to be separated from you and me and the other small boys who are standing about, said boys being the g-a-n-g-u-e, or g-a-n-g, as we would have spelled it. The oil film surrounding the bubble is the counterpart of the silken fabric of the balloon, and bubble and balloon will rise for. the same reason, namely. that the fluid outside it is heavier than the fluid within. In flotation reagent nomenclature the material of which the bubble is made is called the "frother.",

Jan 1, 1930