Details of the Formation of Superstructures in the Process of Ordering in Cu-Pt Alloys

Abstract:

Alloys of Cu-Pt [1] are of interest for research, since the phase transitions "order - disorder" at different concentrations of components form several types of superstructures. In the alloy Cu₃Pt the ordering L1₂ superstructure formed on the basis of fcc lattice. In the ordering of the fcc lattice of the disordered solid solution the equiatomic composition transformed into the L1₁ superstructure with an rhombohedral crystal lattice (a state with an L1₁, whose angles α, β, and γ are other than π/2). A CuPt₃ in an ordered state has an L1₃ superstructure (a state with an L1₃, whose angles α, β, and γ are other than π/2). A possible existence of an ordered phase containing 20 at.% Pt was reported in the literature [2], which corresponds to the composition of Cu₄Pt (type of superstructure was not defined). In other sources, an occurrence of an ordered compound, Cu₇Pt, was predicted, containing 12.5 at.% Pt [3]. Computer experiments performed on the Monte Carlo method, showed that the alloys of the Cu - Pt different composition components undergo phase transformations "disorder - order" from the FCC to the structures of different symmetry [4,11]. This paper presents the results of a study of the structural transformations in the alloys Cu₃Pt, CuPt, CuPt₃ (superstructure L1₂, L1₁, L1₃), containing shear antiphase boundaries (APB) in the planes {111}.

• Periodical: Key Engineering Materials (Volumes 592-593)
• Pages: 321-324
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.592-593.321
• Online since: November 2013
• Authors: Mikhail D. Starostenkov*, Alexandra Chaplygina, Veronika Romanenko
• Keywords: Alloy, Antiphase Boundary (APB), Diffusion, Monte - Carlo Method, Phase Transition, Superstructure, Vacancy

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