Effect of B2 nanoprecipitates on mechanical behavior of TiZrNbVAl lightweight high entropy alloys upon dynamic loading

Abstract

The addition of B2 nanoprecipitates provides a new way to improve the mechanical properties of lightweight high entropy alloys (LHEAs) with body-centered-cubic (BCC) structure. However, the study of B2 nanoprecipitates on BCC-LHEAs is limited to quasi-static tension. In this work, TiZrNbVAl LHEAs with BCC structure was chosen as model alloys and the effect of B2 nanoprecipitates on dynamic mechanical properties of TiZrNbVAl LHEAs was studied. The results show that the introduction of B2 nanoprecipitates not only significantly improves the dynamic strength, but also increases the plasticity from 31 % to more than 46 %, with an increase of more than 48 %. Microstructure evolution proves that during the plastic deformation process, the B2 nanoprecipitates promoted a large number of “second-generation bands” of dislocation in the separation of the first-generation bands, which effectively extended the plastic deformation region to the entire sample and improved the uniform deformation ability of LHEAs. Our results provide a solution for improving the mechanical properties of LHEAs under dynamic/impact conditions.