Lattice Parameters Of Alloys Research Articles

Preparation of nonequilibrium solid solutions of (GaAs)1−xSix

A method using coincident rf sputtering and rf discharge decomposition is shown capable of producing single-crystal, epitaxial, nonequilibrium solid solutions of Si in GaAs with the composition of Si far exceeding the limits reported for the bulk equilibrium phase diagram. Measured values of alloy composition and lattice parameter indicate close correspondence to Vegard's law. High-temperature annealing of epitaxial films demonstrates the ultimate instability of the alloys.

Preparation and Properties of Bulk In1 − xGaxAs Alloys

Single crystals of have been grown by Czochralski techniques for and . Polycrystalline single‐phase material has also been pulled for . Two Czochralski techniques were employed: (i) the sealed system or Gremmelmaier technique, and (ii) the liquid encapsulation technique. Mass spectrographic data have been correlated with alloy lattice parameter determinations on the as‐grown material to yield information on the solidus curve of the system. Hall measurements were made and impurity analyses were performed using the spark source mass spectrometer.

The Hall coefficients of α-phase Ag-Li alloys in the range 6-300°K

Abstract The Hall coefficients of α-phase Ag-Li alloys in the range 0·74-22·5 at. % have been determined over the temperature range 6—300°K. They show a dependence upon solute concentration and upon temperature which is completely different from that previously reported for this system, and this is attributed to the improved metallurgical control of the samples in the present work. The Hall effect data suggest that a relatively large scattering anisotropy for the impurity scattering exists, and this is supported by the magnitude of the observed deviations from Matthiessen's rule. The paper includes new data both for the lattice parameter of α-phase Ag-Li alloys and for the temperature dependence of their electrical resistivities.

Lattice parameters and Curie-point anomalies of iron-cobalt alloys

Lattice-parameter-temperature relationships have been examined for iron-cobalt solutions containing up to 12 wt.% cobalt for temperatures up to approximately 900°C, with particular attention being paid to the Curie-point regions. Cobalt additions progressively reduced the magnitude of the lattice-parameter anomaly previously reported for iron by Ridley and Stuart until at 12 wt.% cobalt no anomaly was observed. The results showed that volume changes resulting from the ferro-magnetic-paramagnetic transition had no significant effect on the room-temperature lattice parameters of iron-cobalt alloys, which show a marked deviation from Vegard's law.

Studies on the heusler alloys—III. The antiferro-magnetic phase in the Cu-Mn-Sb system

A micrographic study of some alloys of the Cu-Mn-Sb system in both the as-cast and heat-treated conditions, revealed the presence of a single phase alloy (lattice parameter, a = 6·088 ± 0·003 A ̊ ) at the composition CuMnSb. Alloys having slightly less copper than the stoichiometric alloy also consisted of a single phase, although quenching was usually necessary to prevent the appearance of a second phase. Alloys with higher copper concentrations, including the alloy of composition Cu 2MnSb, contained an α-Cu solid solution, as well as the intermediate phase. X-ray and neutron diffraction investigations of CuMnSb showed the alloy to have an ordered MgAgAs (Cl b ) type structure with Cu atoms at 0, 0, 0; Mn atoms at 1 4 , 1 4 , 1 4 ; and Sb Atoms at 3 4 , 3 4 , 3 4 Antiferromagnetic reflections appeared in neutron diffraction scans at 4.2°K and were indexed using a magnetic unit cell with twice the edge lengths of the chemical unit cell. The magnetic moments of the manganese atoms were found to be oriented perpendicular to the ferromagnetic (111) planes and parallel to the [111] direction of the rhombohedral magnetic cell. The average magnetic moment per manganese site was determined to be 3·9 ± 0·1 μ B .

Order-disorder transformations at 2:1 composition in the cadmium-mercury system

Order-disorder transformations at both the 2:1 and 1:2 compositions of a binary alloy system have been established for the first time. Low temperature X-ray diffraction and electrical resistivity data confirm the formation of such superlattices in the only intermediate phase of the Cd-Hg system, which extends from 35 to 85 at. % mercury. The transformations occur at −10 and −12°C on cooling in alloys whose compositions approximate to the formulae Cd 2Hg and Hg 2Cd respectively. The superlattices conform to the “Strukturbericht” type C11b, which occur in several binary alloy systems in the ordered form only. Each cell of the ordered structure consists of three unit cells of the disordered structure stacked in the c direction. Accurate determination of the lattice parameters of alloys in the Cd-Hg intermediate phase region has been made to clear earlier uncertainties. Some modifications are proposed in the Cd-Hg phase diagram.

Paramagnetic Susceptibility, Electrical Resistivity, and Lattice Parameters of Nickel-Rich Nickel-Tantalum Alloys

The paramagnetic susceptibility, electrical resistivity, and lattice parameters of nickel-rich nickel-tantalum solid solutions (10 compositions) have been studied. The paramagnetic measurements extend to about 1500°K. The resistivities have been obtained at 4.2°, 77.2,° and 297.0°K. The lattice parameters of samples quenched from 1473°K were determined at 298°K. All these data indicate that the influence of tantalum on the physical properties of nickel is very similar to that of niobium. It is demonstrated by means of the magnetic susceptibility measurements that the generally accepted Curie-Weiss law, with an additive temperature-independent susceptibility term, is not applicable to the solid solutions of tantalum in nickel. The susceptibility and resistivity data are briefly discussed from the viewpoint of recent theoretical and experimental developments. The lattice parameters are analyzed using the previously suggested atomic volume scheme and elasticity theory. The agreement between the experimental values and the predictions is satisfactory.

Coefficients of Thermal Expansion for Zirconium

The expansion coefficients of hexagonal (α) zirconium have been calculated from the lattice parameters of both low and high hafnium alloys in the range 0° to 600°C. It is found that the coefficients are straight-line functions of the temperature and that the effect of hafnium is to depress the mean coefficients by about 1 pct at room temperature and 9 pct at 600°C. The cubic (β) form was stabilized so that its coefficient could be determined from 400° to 900°C.

A Nickel-Gallium Superlattice (Ni3Ga)

THE nickel–gallium system has been investigated by Hellner1, who stated that the nickel solid solution extended to 28 atomic per cent gallium, while the lattice parameter increased to 3.591 A. at the solubility limit. However, in the course of a systematic investigation of nickel alloy lattice parameters, which will be published in due course elsewhere, we have found a Ni3Ga phase with the Cu3Au super-lattice structure. The nickel–gallium system is similar to the nickel–aluminium system2 in that the ordered phase has a relatively small homogeneous range, while on the nickel-rich side a wide heterogeneous range is found at low temperatures, producing a considerable difference of lattice parameter of the two co-existing cubic phases.

Effect of Temperature on the Lattice Parameters of Magnesium Alloys

Effect of Temperature on the Lattice Parameters of Magnesium Alloys

Lattice parameters of magnesium alloys

The effect of solute additions on the lattice parameters of magnesium alloys is reported. Empirical equations are derived from the data which have allowed the calculation of the lattice parameters of ternary solid solutions from binary data. The data are taken both from the literature and from additional experimental work.

New fusible alloys:Remarks on determining the melting point of metals

ZrCo alloys with Ti, Sc, Ni, Fe substitution (Zr0.8Ti0.2Co, Zr0.8Sc0.2Co, ZrCo0.8Ni0.2, ZrCo0.8Fe0.2) were prepared via arc-melting method, and then products before and after hydrogenation were characterized by X-ray diffraction. Results showed that the crystal structure of ZrCo alloys substituted with Ti, Sc, Ni and Fe substitution formed cubic phase, and the lattice parameters of ZrCo alloys and these hydrides decreased with Ti substituted, while increased with Sc, Ni, Fe substitution. The dehydrogenation pressure composition isotherms for all these alloys were obtained in the temperature range between 523 K and 623 K, and it was found that desorption plateau pressure increased in order of ZrCo0.8Fe0.2 < ZrCo < Zr0.8Sc0.2C < ZrCo0.8Ni0.2 < Zr0.8Ti0.2Co. Meanwhile, the enthalpy and entropy change for hydrogen desorption were calculated. And the kinetics of hydrogen-induced disproportionation in desorption mode for all these alloys was also investigated. Results demonstrated that the rate and extent of disproportionation of ZrCo alloys decreased with Ti substitution, while increased with Sc, Ni and Fe substitution. Thermal analytical method (DSC) was carried out to investigate the mechanism of thermal stability change of ZrCo alloys after Ti, Sc, Ni, Fe substitution. It could be inferred that the effect of element substitution on disproportionation of ZrCo alloys was caused by the radius change of hole sizes of hydrogen occupation sites.