Research Progress on Plastic Deformation Induced by HCP to FCC Phase Transformation in Hexagonal Close-Packed Metals

Abstract

Plastic deformation plays a critical role in improving the formability and mechanical performance of metals. In titanium, zirconium, and hafnium, slip and twinning are the primary deformation mechanisms, while phase transformations also contribute significantly. This article summarizes recent advances on the hexagonal-close-packed (HCP) phase to face-centered-cubic (FCC) phase transition in these metals, focusing on the mechanism of HCP-to-FCC phase transition-induced plastic deformation and its orientation relationships (ORs), phase transition mechanism, and influencing factors. The plastic deformation mechanism includes the formation and movement of dislocations and twins, the interaction with phase boundaries, and grain refinement. The three types of ORs are basal plane type (B-type), prismatic plane type (P-type), and the third type. The B-type transformation involves Shockley partial dislocation slip on the basal plane (0001), while the P-type and third type occur via slip on prismatic planes {10$\overline{1}$0}. The influencing factors of phase transformation include stress, strain, grain size, temperature, alloying elements, and others. The problems of phase transformation are proposed and summarized to provide reference for subsequent research.