An Ultra‐Low Modulus of Ductile TiZrHfTa Biomedical High‐Entropy Alloys through Deformation Induced Martensitic Transformation/Twinning/Amorphization

Abstract

Biomedical alloys are paramount materials in biomedical applications, particularly in crafting biological artificial replacements. In traditional biomedical alloys, a significant challenge is simultaneously achieving an ultra‐low Young's modulus, excellent biocompatibility, and acceptable ductility. A multi‐component body‐centered cubic biomedical high‐entropy alloy (Bio‐HEA), which is composed of non‐toxic elements, is noteworthy for its outstanding biocompatibility and compositional tuning capabilities. Nevertheless, the aforementioned challenges still remain. Here, we propose a method to achieve a single phase with the lowest Young's modulus among the constituent phases by precisely tuning the stability of the body‐centered cubic phase in the Bio‐HEA. The subtle tuning of the body‐centered cubic phase stability also enables the induction of stress‐induced martensite transformation with extremely low trigger stress. The transformation‐induced plasticity and work hardening capacity were achieved via the stress‐induced martensite transformation. Additionally, the hierarchical stress‐induced martensite twin structure and crystalline‐to‐amorphous phase transformation provide robust toughening mechanisms in the Bio‐HEA. The cytotoxicity test confirmed that this Bio‐HEA exhibited excellent biocompatibility without cytotoxicity. In conclusion, our study provides new insights on the development of biomedical alloys with a combination of ultra‐low Young's modulus, excellent biocompatibility, and decent ductility.This article is protected by copyright. All rights reserved