Manganese Addition Induced “Maze-Like” Nanostructure Enables Lightweight Medium Entropy Alloys with Large Uniform Plastic Deformation

Abstract

Body-centered cubic (BCC) structured lightweight high/medium entropy alloys (HEAs/MEAs) are a promising class of structure materials, but poor strain hardening ability limits their actual applications. This work proposes a method of improving the strain-hardening ability of a BCC lightweight MEA via a small addition of Mn element. The Mn containing TiVZr MEA exhibits a “maze-like” nanostructure that promote dislocation multiplication during deformation, improving strain hardening ability and uniform elongation (>10%). Large difference in lattice parameter between Mn and TiVZr solid solution matrix contributes to significant solid solution strengthening and hence high specific tensile yield strength (~180 MPa·cm3/g).

Keywords: Lightweight medium entropy alloys, Mn addition, Spinodal decomposition, Strain hardening