Microstructure evolution and mechanical properties of Ti–8Nb–2Fe-0.2O alloy with high elastic admissible strain for orthopedic implant applications

Publication date: Available online 22 January 2020Source: Progress in Natural Science: Materials InternationalAuthor(s): Yu Fu, Junshuai Wang, Wenlong Xiao, Xinqing Zhao, Chaoli MaAbstractA Ti–8Nb–2Fe-0.2O (wt.%) alloy with high strength, high elastic admissible strain (δ) and low cost was designed using d-electron theory combined with electron-to-atom ratio (e/a‾) approach. Interstitial oxygen was introduced to strengthen the matrix of the alloy. The β-solution treated alloy was mainly composed of α″ martensite with internal {111}α″ type I nano-twins. The α″ martensite with hexagonal-like crystal structure caused by interstitial oxygen showed a high strength of 1.1 GPa but limited ductility. The alloy generated equiaxed fine-grained α phase embedded by β matrix via hot rolling and subsequent annealing in α + β phase field. The obtained alloy indicated a good combination of mechanical properties with ultimate tensile strength, Young’s modulus, ductility and δ value of 1029 MPa, 74 GPa, 21% tensile elongation and 1.32%, respectively. These findings demonstrate that interstitial oxygen and martensitic nano-twins can be used to strengthen the soft α″ martensite and high elastic admissible strain can be obtained by formation of equiaxed fine-grained α phase embedded by β matrix in this Ti–8Nb–2Fe-0.2O alloy for orthopedic implant.Graphical abstract
Source: Progress in Natural Science: Materials International - Category: Materials Science Source Type: research