Microstructural evolution and phase transitions in porous Ta/Cu alloys under high strain rates.

Tantalum (Ta) and its alloys are widely used in electronics, dental implants, aerospace, and nuclear industries. Ta-based medical implants have also attracted considerable attention in recent years. However, challenges such as thermal conductivity, oxidation resistance, antibacterial properties, and the mismatch between bone and implant mechanical properties remain major concerns across various applications. The addition of alloying elements, such as copper (Cu), to Ta reduces bacterial adhesion in medical applications, while also improving thermal conductivity and oxidation resistance, making it beneficial for high-temperature environments. Furthermore, incorporating porosity into Ta-based materials mitigates stress shielding in implants, reduces weight, and enhances thermal dissipation in advanced engineering applications. While numerous studies have investigated the mechanical and physical properties of Ta-based alloys, the combined influence of porosity and alloying elements on the mechanical response of these biomaterials has not been systematically studied. This study employs molecular dynamics (MD) simulations to analyze the mechanical response and microstructural evolution of porous Ta/5 wt% Cu alloys under uniaxial tensile loading. Our results demonstrate that optimizing strain rates and introducing pores can modulate the mechanical characteristics of Ta/Cu alloys. Increasing the strain rate from 5 × 10 to 5 × 10 s enhances properties due to the rapid BCC-to-FCC phase transformation at high strain rates, while increasing porosity from 0 to 10% reduces yield stress and elastic modulus by 12% and 14%, respectively. Moreover, the influence of porosity on deformation-induced microstructural transformations, such as twinning behavior and crystallographic changes, is examined. The study offers insights into designing porous Ta-based alloys with improved mechanical performance and microstructural characteristics.