Enhancing strain hardening in TiVZr lightweight medium entropy alloys with Mn-induced maze-like nanostructure

Although lightweight high/medium entropy alloys (HEAs/MEAs) with a body-centered cubic (BCC) structure are a promising class of structural materials, their actual applications are limited due to their low strain-hardening ability. This work proposes a method of enhancing the strain-hardening ability of TiVZr lightweight MEA by a small amount of Mn element. The TiVZr_0.1Mn_0.1 exhibits a “maze-like” nanostructure that promotes dislocation multiplication during deformation, resulting in improved strength, strain hardening ability, and uniform elongation (>10 %). The considerable difference in lattice parameters between the Mn and TiVZr solid solution matrix contributes to significant solid solution strengthening, demonstrating a high specific tensile yield strength (∼180 MPa cm³/g).