Study of phase equilibria in the Al - Pd - Re system

Scanning and transmission electron microscopy have been combined with x-ray diffraction to examine the phase equilibria in the Al - Pd - Re system at 1000°C for compositions from 50 to 100 at.% Al, and the corresponding isothermal section has been constructed. The binary monoclinic Al₃ Re phase has been observed for the first time. It is confirmed that there is a stable icosahedral phase in this system. The boundaries to its homogeneity region have been determined and the phase equilibria in which it participates.     

Phase equilibria in the system Al-Rh

Methods of differential thermal analysis, x-ray diffraction, microstructural analysis and electron probe microanalysis are used to study alloys of the Al-Rh system over the whole concentration range. It is established that the phase of equiatomic composition AlRh melts congruently at 2060°C and it has an extended range of homogeneity (45.1–54.2 at.% Rh). The solubility of aluminum in rhodium reaches 9 at.%, decreasing to 6 at.% at 850°C. Coordinates are determined for the eutectic point l ⇆ AlRh + 〈Rh〉 as 70 at.% Rh and 1715°C. The existence of intermediate phases, their crystal structure, and also the method of forming phases in the field of composition rich in aluminum given in publications are confirmed. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(449), pp. 48–56, May–June, 2006.     

Economical technology for cryoproduct storage and delivery

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 11, pp. 22–23, November, 1992.     

Phase Equilibria in the Melting - Crystallization Region for Alloys in the Ti - TiNi - Sc0.53Ni0.47 - Sc Subsystem

Physicochemical analysis methods have been applied to the phase equilibria in the Ti - TiNi - Sc_0.53Ni_0.47 - Sc subsystem of the Ti - Ni - Sc ternary system. No ternary compounds are found in the subsystem. Isomorphous phases based on Ti₂Ni and Sc_0.72Ni_0.28 form continuous series of solid solutions (η) at subsolidus temperatures, as do the equiatomic compounds TiNi and Sc_0.53Ni_0.47. The crystallization of the η phase in the ternary system is incongruent, as in the binary systems Ti - Ni and Sc - Ni. The solidus surface for the Ti - TiNi - Sc_0.53Ni_0.47 - Sc subsystem has a nonvariant four-phase reaction of transition type at 830 °C. The compositions of the alloys that take part in it extend to the Sc - Ni side.     

Ordering in the carbide W2C and phase equilibria in the tungsten — carbon system in the region of its existence

We have studied alloys in the W - C system with compositions 24 to 48 at.% C, melted in an arc furnace, homogenized and quenched from temperatures of 1450°C to 2650°C or cooled stepwise from a subsolidus temperature down to 850°C, and annealed for a prolonged period at this temperature or at temperatures close to it. We studied the specimens by x-ray single-crystal and powder diffraction, metallography, and differential thermal analysis. We have shown that the carbide W₂C exists in two modifications: an hexagonal phase with structure of type L′₃ crystallizes from the melt, which at T ≈ 1850°C transforms to an ordered hexagonal phase of the ε-Fe₂N type. The latter, for a carbon content of about 32 at.% and T ≈ 1250°C, also decomposes according to a eutectoid reaction to 〈W〉 and WC. This decomposition is accompanied by formation of a metastable phase of the ξ-Fe₂N type as an intermediate. Taking the results obtained and literature data into consideration, we have corrected the phase diagram for the W - C system.     

Formation of Quasicrystals and Related Structures in Systems of Aluminum with Transition Metals. Part 1. Binary Systems Formed by Aluminum with 3d Metals

Quasiperiodic phases (quasicrystals) with symmetries forbidden by classic crystallography have been observed in systems of aluminum with transition metals. In binary systems, these phases are metastable; they were obtained for the first time by rapid solidification of melts. We consider the formation of the quasicrystals and we refine the phase diagrams for binary systems A – 3d-M (from V to Ni) in which quasicrystals have been observed.