Showing papers on "Ternary operation published in 1971"

The effect of ternary additions on the decompositon of metastable beta-phase titanium alloys

Abstract: The effect of ternary additions of Al, O, Sn, and Zr on the decomposition of metastable Ti-Mo and Ti-V Β-phase alloys has been studied. It is shown that all these additions reduce the volume fraction, upper temperature limit of formation, and time of stability of the Ω phase. These results have been contrasted to earlier work in binary alloys in which misfit was shown to be a primary factor in determining the morphology and range of stability of the Ω phase. In the ternary alloys the particle morphology can still be explained in terms of misfit, but other considerations appear to be predominant in determining the range of stability. Results are also presented on a phase separation reaction which occurs at higher alloy contents and which has an important influence on the morphology of α-phase precipitation.

Grain refinement in aluminum alloyed with titanium and boron

Abstract: The aluminum corner of the ternary Al-B-Ti diagram was explored. A eutectic: Liq — Al + TiAl3 + (Al, Ti)B2 was found at approximately 0.05 wt pct Ti, 0.01 wt pct B; 659.5‡C. TiB2 and A1B2 form a continuous series of solid solutions, but no distinct ternary phase was found. The addition of boron to aluminum-titanium alloys expands the field of primary crystallization of TiAl3 toward lower titanium contents and steepens the liquidus. In equilibrium conditions, pronounced grain refinement is found only in alloys in which TiAl3 is primary and nucleates the aluminum solid solution before any other impurity can act. The peritectic reaction facilitates this priority but it is not necessary for grain refinement. Because of the low diffusivity of titanium and boron in aluminum, equilibrium is seldom attained and in commercial practice grain refinement by TiAl3 is found also outside its equilibrium field of primary crystallization.

Dielectric Theory of Tetrahedral Solids: Application to Ternary Compounds with Chalcopyrite Structure

Abstract: The Phillips---Van Vechten dielectric theory of binary tetrahedral compounds and Levine's bond-charge model are formulated in terms of macroscopically defined linear and nonlinear bond polarizabilities. This formulation allows the determination of the linear and nonlinear optical properties of tetrahedral solids. As an illustration, the case of ternary compounds with chalcopyrite structure is considered. Theoretical and experimental results are in good agreement.

Precipitation-hardening characteristics of ternary cobalt - aluminum - x alloys

Abstract: Five precipitation-hardenable ternary cobalt-base alloy systems containing 4.25 weight percent aluminum with titanium, niobium, tantalum, molybdenum,. and tungsten as the third element were melted and evaluated as to their precipitation-hardening characteristics. Hardening phases were electrolytically extracted from alloys aged up to 1000 hours in the 600°C to 900°C temperature range. Based upon the evaluation of these systems, three quartenary alloys with compositions Co-4Al-15Cr-10Ta, Co-4Al-15Cr-20Mo, and Co-4Al-15Cr-25W were melted and simi­ larly evaluated after aging for times from 0.1 to 1000 hours at 800°C. The results of the investigation of the ternary al­ loys showed that Ti additions promoted the highest percent­ age increase in hardness, but that overaging of the AlC^Ti hardening phase was very rapid. The effects of the Nb and Ta additions to the Co-4Al matrix were somewhat similar in that both were considerably more effective as solid solution strengtheners than as pre­ cipitation hardening agents. Hardening in the Ta alloys was the result of the presence of primary and precipitated yCo2Ta (MgNi2 type) which, upon aging, transformed to the cubic xi aCo-jTa. Similarly, in the alloys containing Nb, the Laves phase Co2Nb (MgK^ type) was generally present. Two phases previously reported in the literature for the Co-Nb binary system were confirmed. The Co-4Al-5Nb alloy aged for 1000 hours at 700°C contained an ordered fee phase with O aQ = 3.655 A, while this same alloy aged at 800°C contained O a hexagonal phase having the parameters a = 5.9 4 A and c = 6.89 A. The cellular precipitation of Co^Mo in the Co-Al-Mo alloys produced very high hardnesses in that alloy system. Temperatures of 900°C were required to overage these struc­ tures within the 1000-hour test interval. In the Co-Al-W systems, an ordered fee superlattice, O or coherent precipitate, having a parameter of aQ = 3.5 95 A was found. Precipitation of this phase resulted in continu­ ous increases in hardness for aging times up to 1000 hours at 800°C. Additions of 15 weight percent Cr to the basic Co-4Al-10Ta, Co-4Al-20Mo, and CO-4A1-25W alloys changed their aging behavior; and in the case of the latter two al­ loys, the R and Mu phases, respectively, appeared. Aluminum additions to alloys of Co containing the refractory metals or Ti generally result in a stabilization of the fee Co matrix and a resulting decrease in the tend­ ency for the formation of non-cubic phases in the matrix. This effect seemed especially strong in the alloys containing

The determination of activities by mass-spectrometry—some additional methods

Abstract: Further consideration is given to the determination of the thermodynamic properties of metallurgical solutions by mass-spectrometric analysis of the equilibrium vapor effusing from a Knudsen cell. Equations are presented which permit the application of the integration of ion-current ratios to complex species, thus avoiding problems caused by fragmentation ionization. The method is applied to a limited study of the Bi-Te system at 750°C. Ternary systems are considered and the method for the determination of the properties from measurements of a pair of ion-currents is demonstrated. Equations are also derived for the treatment of a ternary system which is saturated with respect to an involatile component. Finally, a method is presented for correcting the monomer-dimer ratio technique of Berkowitz and Chupka for fragmentation ionization effects.

Molecular thermodynamics of gases in mixed solvents

Abstract: The general thermodynamic relation between Henry's constant for a solute in a mixed solvent and Henry's constants for the solute in the pure solvents is discussed in terms of limiting activity coefficients. The inadequacy of several common excess free energy expressions is shown, and results are presented for a form of Kirkwood-Buff solution theory based on pair distribution functions. Several unknown integrals in the theory are approximated by an empirical function of solvent composition and of solvent properties which generally predicts experimental data for gases in both simple and complex binary solvents with good accuracy. Prediction of fugacities of gaseous components in ternary and higher solvents and in nonideal solutions is considered.

Growth and Characterization of Liquid‐Phase Epitaxial InAs1−xPx

Abstract: Liquid‐phase epitaxial layers of InAs1−xPx were grown in the range of 0 < x < 0. 735 on {111} InP substrates. The ternary phase diagram was calculated using Darken's quadratic formalism to describe the ternary liquid which is in equilibrium with a regular pseudobinary solid solution. A number of liquidus isotherms were experimentally determined and found to be in good agreement with the calculated phase diagram. The composition of the grown layers was determined by lattice‐constant measurements assuming that Vegard's law was obeyed. The band gap was determined by photoluminescence at 77 and 300 °K, and was fitted to the form of Eg = A + Bx + Cx2, where A = 0. 421, B = 0.714, and C = 0. 281 eV at 77 °K. The specimens were n type as determined by Van der Pauw measurements.

Theory of Luminescent Efficiency of Ternary Semiconductors

Abstract: The luminescent efficiency is calculated for a ternary semiconductor, wherein the total electron concentration is divided between the direct and indirect conduction‐band minima. In each valley, the rate equations are determined by radiative, nonradiative, and intervalley transfer times. Although such intervalley transfer times are unimportant at 300°K for efficient material, they are found to be important at 300°K when the internal radiative efficiencies are less than 1%. Furthermore, since phonon cooperation is mandatory for transitions between the direct and indirect valleys, the intervalley transfer times become quite long (>10−9 sec in GaAsP) at lattice temperatures below 77°K. In order to compare the analytical expressions of luminescent efficiency with experiment, it was necessary to derive expressions for the external quantum efficiency of a p‐n junction in a direct band‐gap material. The external electroluminescent efficiency is derived in terms of the junction depth, diffusion length, and absorption coefficient. For the particular case of radiative transitions between free electrons and holes, the predicted ternary electroluminescent efficiencies are in agreement with published experimental results on GaAsP. Furthermore, application of the efficiency expressions to the case of deep impurity emission associated with Si in GaAlAs leads to good agreement with published experimental data on this system. Finally, it is shown that the nonradiative transitions associated with the alloying process are unimportant for most direct band‐gap ternaries, as well as inefficent indirect band‐gap compositions.

Thermodynamic modeling of binary and ternary metallic solutions

Abstract: A model is proposed for describing heat of mixing behavior in binary and ternary metallic solutions The binary model, which has the form, ΔH M =α1 X 2 X B +α2 X A X 2 −α3 X 2 X 2 , whereX A andX B are mole fractions of componentsA andB and α1, α2, and α3 are constants, is applied to the heat of mixing values for 84 solid and liquid systems and the results are compared with the subregular model The ternary model, which is composed of the sum of the binary equations and a ternary interaction term of the form α ABC X A X B X C , was applied to the Bi−Cd−Pb, Cd−Pb−Sn, and Cd−Pb−Sb systems There was excellent agreement both as to the shapes of the isoenthalpy of mixing curves and as to the heat of mixing values in the ternary systems when the model was used to predict the experimental values

Phase Separation Phenomena in Ternary Systems and Selective Solvation

Abstract: — 660 C für Silbernitrat und für Natriumnitrat und Kaliumnitrat + 30 °C bzw. 4-10 °C. In Übereinstimmung mit einer Theorie von C. Wagner ist die Änderung der kritischen Lösungstemperatur eines ternären Systems abhängig von der Löslichkeit der dritten Substanz. Man erhält für verdünnte Elektrolytlösungen eine Proportionalität zwischen der Temperaturänderung und der zweiten Ableitung der Löslichkeit nach dem Molenbruch. Der Zusammenhang zwischen Löslichkeit und selektiver Solvatation ist angedeutet.

Mapping of the oxidation products in the ternary Co-Cr-Al system

Abstract: Ternary Co-Cr-Al alloy oxidation data, detailing kinetics, products, mechanisms, resistance behavior and rate

The reaction of selected lanthanide carbides with platinum and iridium

Abstract: The dicarbides of yttrium, cerium and erbium have been reacted with platinum and iridium by heating in the range 1000°–1600 °C. The reduction of the carbides leads to the formation of a number of rare-earth platinides and iridides and free carbon. No ternary compounds were found. Ternary diagrams have been deduced. From the reactions, lower limits can be set for free energy of formation of the intermetallic compounds.

A single-parameter equation for isothermal vapor-liquid equilibrium correlations

Abstract: The Wilson equation is modified so that it contains only one adjustable constant per binary system. In describing binary behavior the new equation is inferior to the original Wilson but superior to the Van Laar equation. In developing ternary behavior from binary data, the new equation seems to be comparable to the original Wilson but definitely superior to the Van Laar equation. Binary and ternary vapor-liquid equilibrium behavior has been successfully predicted from one γ° value per binary only.

The directional solidification of Al−Cu−Mg monovariant alloys

Abstract: Alloys whose compositions lie along the ternary monovariant line between the binary Al−Cu and the ternary Al−Cu−Mg eutectics were directionally solidified at rates of 0.17 to 20 cm per hr. Both plane front and cellular or dendritic structures were obtained. A criterion for the breakdown of plane front growth based on constitutional supercooling was found to be valid at both ends of the monovariant line. It was found that the amount of ternary eutectic present at the boundaries of cellular or dendritic structures may be closely predicted by the nonequilibrium lever rule for freezing.

Theory of the snoek effect in ternary b.c.c. alloys

Abstract: Interstitial atoms in ternary b.c.c. alloys exhibit hydrostatic relaxation, if an applied stress has a dilatational stress component. The effect is absent in binary alloys. Hydrostatic relaxation, in contrast to orientation relaxation effect, involves long-range diffusion; in order to understand various aspects of the process, calculations are made for imaginary lattices. Internal friction curves are computed for different solute concentrations in a real three-dimensional lattice. The height and the temperature of the peak are compared for hydrostatic relaxation and orientation relaxation.