COMPUTATIONAL STUDY ON THE Cu-RICH SIDE OF ALUMINUM-COPPER PHASE DIAGRAM

Abstract

Cu-rich side of Al-Cu phase diagram has not been studied extensively as the Al-rich side. It is well established that a one-phase (α phase) exists at 300oC between the 82% Cu and pure Cu, and at the eutectic temperature (1032oC) between 86% Cu and pure Cu, α phase, when quenched from above 600oC and subjected to annealing below about 300oC, or deformation, show ordering effects in resistivity, heat capacity, diffuse X-ray, microstructure, and in mechanical properties. This has been studied to determine whether these effects are due to short-range or long-range ordered domain [1]. The present computational study is to assess the Cu-rich side of Al-Cu phase diagram for Cu concentration larger than 75%, and between 300K and 1000K. Molecular dynamics, Hybrid Molecular Dynamics/Monte Carlo, and DFT simulations are used to investigate the possibility of phase separation in this range of phase diagram. It is shown that a two-phase region exists below about 900K, and that phase separation takes place by nucleation and growth, and not by spinodal decomposition. Also, it is shown that these two phases are random FCC α solid solution, and intermetallic α2.