Influence of multi-axial compression on the microstructure evolution and properties of Ti-27Nb-2Mo-2Zr-2Sn
摘要
In this study, the application of severe plastic deformation technology to biomedical titanium alloys with stress-induced martensitic transformation (SIMT) was investigated. Through the use of X-ray diffraction analysis, transmission electron microscopy analysis, and tensile testing, the influence of multi-axial compression (MAC) processing on the microstructure evolution and properties of the Ti-27Nb-2Mo-2Zr-2Sn alloy was evaluated. The findings demonstrated that a combination of SIMT and MAC could result in significant grain refinement. MAC technology enabled the generation of β grains smaller than 100 nm in the Ti-27Nb-2Mo-2Zr-2Sn alloy. Effective grain refinement was found to be closely associated with the evolution of stress-induced α″ martensitic phases. Furthermore, after MAC processing, the strength of the alloy increased due to the increased levels of dislocation density and grain refinement. Conversely, the reduction in the elastic modulus resulted from the dissolution of nonthermal ω phases and α″ martensitic phases. In addition, the high-density dislocation and β/α″ interface introduced by MAC pretreatment greatly accelerated the aging precipitation process at 550 °C. Notably, the Ti-27Nb-2Mo-2Zr-2Sn alloy exhibited an improved tensile strength to elastic modulus ratio (18.9 × 10−3) and a suitable corrosion resistance after 6 MAC processing cycles, highlighting its potential for future application as an orthopedic implant material.