CVM Calculation Of The Fe–Cr–Al Phase Diagram With Ab Initio

In this paper we investigate the phase diagram of Fe-Cr,Fe-Al and Al-Cr binary alloys with the Cluster Variation Method?CVM?,in which the parameters used are obtained by first principles calculations.To improve the phase diagram we consider both FCC and BCC structures at the same time while other people usually consider one structure.The main features near Fe side of the experimental phase diagram of Fe-Al alloy are produced.Based on the method,we calculate the phase diagrams of three binary alloys of Fe-Al,Fe-Cr and Cr-Al which consider both FCC and BCC structure at the same time.The result suggest that Fe and Cr are BCC structure however Al is FCC.The stable intermetallic phase of Fe-Al alloy are FeAl-B2 phase and Fe₃Al-D0₃ phase,both on the Fe element side.Moreover the distribution of FeAl-B2 phase and Fe₃Al-D0₃ phase is in good agreement with the experimental result.There is no stabled intermetallic phase in Fe-Cr alloy at s finite temperature considering both FCC and BCC structure.The stable intermetallic phase of the Al-Cr alloy includes the Al₃Cr-L1₂ phase of the FCC structure and the AlCr-B32 phase of the BCC structure.With Cluster Variation Method we find all stable intermetallic phases showing in experiment results except for the B2 and D0₃ in the Al-Cr alloy which may be not the most stable intermetallic phase.In the future,we will consider more crystal structures and more elements to provide the theoretical instruction for the synthesis and research of the alloy phase.