Boosting biocompatibility and mechanical property evolution in a high-entropy alloy via nanostructure engineering and phase transformations

Author(s)

Nguyen, Thanh Tam ; Edalati, Payam ; Dangwal, Shivam ; Pereira, Karina Danielle ; Cremasco, Alessandra ; Floriano, Ricardo ; Luchessi, Augusto Ducati ; Edalati, Kaveh

• Document type: Journal article
• Source: Journal of Alloys and Compounds; v. 1035, p. 12-pg., 2025-07-05.

Abstract

High-entropy alloys (HEAs), as multi-component materials with high configurational entropy, have garnered significant attention as new biomaterials; still, their low yield stress and high elastic modulus need to be overcome for future biomedical applications. In this study, nanograin generation is used to enhance the strength and phase transformation is employed to reduce the elastic modulus of a biocompatible Ti-Zr-Hf-Nb-Ta-based HEA. The alloy is treated via the high-pressure torsion (HPT) process, leading to (i) a BCC (body-centered cubic) to omega phase transformation with [101]omega//[011]BCC and [211]omega//[121]BCC through a twining mechanism, (ii) nanograin formation with a mean grain size of 20 +/- 14 nm, and (iii) dislocation generation particularly close to BCC-omega interphase boundaries. These structural and microstructural features enhance hardness, increase tensile strength up to 2130 MPa, achieve tensile elongation exceeding 13 %, reduce elastic modulus down to 69 GPa and improve biocompatibility. Additionally, the HEA exhibits improved anodization, resulting in a homogenous distribution of oxide nanotubes on the surface with a smaller tube diameter and a higher tube length compared to pure titanium. These remarkable properties, which are engineered by the generation of defective nanograins and the coexistence of BCC and metastable omega phases, highlight the potential of HEAs treated using severe plastic deformation for future biomedical usage, particularly in the orthopedic sector. (AU)

• FAPESP's process: 22/03024-7 - Structure, processing and properties of advanced multicomponent alloys for biomedical and energy storage applications
• Grantee: Ricardo Floriano
• Support Opportunities: Research Grants - Initial Project
• FAPESP's process: 23/07884-3 - Processing and characterization of mechanical and biocompatibility properties of (TiZrNbTa)90Cu10-xAgx and (TiZrNbMo)90Cu10-xAgx (X = 0, 2.5, 5.0, 7.5 and 10 at%) multicomponent alloys designed for the biomedical applications
• Grantee: Payam Edalati
• Support Opportunities: Scholarships in Brazil - Doctorate