High Specific Yield Strength Tizralnbv Lightweight High-Entropy Alloys Via Coherent Nanoprecipitates Strengthening

Abstract

High specific strength and good ductility of lightweight high-entropy alloys (LHEAs) are important for their engineering applications. This work develops a body-centered-cubic (BCC) non-equiatomic system TiZrAlNbV LHEA containing ordered BCC-coherent nanoprecipitates (B2-CNs) with high content (~32%) via tailoring aging treatment. The contribution of introduced B2-CNs strengthening is as high as ~20% to yield strength of the LHEA from dislocation-shearing mechanism, resulting in a great specific yield strength (SYS) of ~202 MPa·m 3 /kg. And the BCC/B2-structured LHEA maintains a considerable fracture strain of ~25%, which is ascribed to cross-slip facilitated during plastic deformation stage. Our results provide a guide for LHEAs to overcome strength-ductility trade-off for structural applications.

Keywords: Lightweight high-entropy alloys, Coherent nanoprecipitates strengthening, Microstructure evolution, Mechanical properties