Theoretical investigation of A-element atom diffusion in Ti2AC (A=Sn, Ga, Cd, In, and Pb)

The phase stability and mechanical properties of Ti(2)AC (A=Ga, Cd, Sn, In, and Pb) have close relationship with the behavior of group-A element atoms in these compounds. This letter shows that although the Al, Ga, and In (or Si, Sn, and Pb) are in the same group, the migration energy and vacancy formation energy of group-A atom in Ti2GaC/Ti2InC (or Ti2SnC/Ti2PbC) are noticeable lower than those in Ti2AlC (or Ti3SiC2). The present results are helpful for a better understanding of easy out diffusion and self-extrusion of group-A atoms in these compounds.