Atomic packing efficiency and phase transition in a high entropy alloy

With the increasing of Al content in a high entropy alloy of Ti0.5CrFeCoNiAlxCu1−x, the phase structure of face centered cubic (FCC) transits to body centered cubic (BCC), namely from a structure with high atomic packing efficiency (APE) to a lower one, and the compressive strength increases from 1650 MPa to 2697 MPa. The phase transition and the strength increases are explained by the lattice distortion.