Achieving excellent strength-ductility synergy of Ti6Al4V alloy produced by powder metallurgy and thermo-mechanical treatment

This study aimed to enhance the mechanical properties of Ti6Al4V alloy through powder metallurgy and thermo-mechanical treatment (TMT). By engineering a fine primary & alpha; phase (& alpha;p) and heterogeneous martensite (& alpha;& PRIME;) microstructure, comprising fine martensite laths (FMLs) and coarse martensite laths (CMLs), we achieved an exceptional combination of strength ab-1148.15 MPa and ductility & epsilon;f-24.32%. Detailed TEM analysis revealed variations in nanohardness between & alpha;p and & alpha;& PRIME; regions, strain partitioning between the two constituents, and a strain gradient from the & alpha;p/& alpha;& PRIME; interface to the grain interior of & alpha;p and & alpha;'. This activated a large number of geometrically necessary dislocations (GNDs) near the interface, mostly with components, contributing significantly to the alloy's extraordinary work-hardening abilities. Strengthening of Ti6Al4V alloy was mainly attributed to the formation of hierarchical nanotwins and solid solution of Al elements in & alpha;p and & alpha;& PRIME; , effectively impeding dislocation motion. These results open up possibilities for obtaining Ti6Al4V with high strength and ductility synergistically, with potential applicability to other materials.