抄録
The effect of Ta content on Young's modulus and microstructure of binary Ti-Ta quenched alloy was investigated in order to find a Ta content that gives the suitable Young's modulus for biomedical applications. For this purpose, the ingots of Ti-Ta binary alloys with different mass percents of Ta from 10% to 80% were melted by tri-arc furnace under argon protection. The ingots were homogenized at 1273K for 21.6ks, and then rolled to the plate of 3mm thick by total reduction of 80%. The rolled plates were then subjected to solution treatment at 1123K, which is above b transus temperature, for 3.6ks followed by ice water quenching. The heat treatment was carried out in vacuum. The rectangular plates with a size of 55x10x2(mm)^3 were machined from the heat-treated plates, and used to measure dynamic Young's modulus at room temperature by the resonance method. The microstructure and phase constitution were examined using an optical microscopy and a X-ray diffraction analysis, respectively. The experimental results show that Young's modulus of binary Ti-Ta alloy depends on both the microstructure and Ta content. The Ti-Ta alloys with mass percents of 30% and 70% have the minimum Young's modulus under the given solution treatment. The microstructure of Ti-Ta quenched alloy is very sensitive to Ta content. The quenched alloy exhibits HCP martensite, alpha prime, structure at a Ta content between 0 and 20mass%, orthorhombic martensite, alpha double prime, structure at a Ta content between 30 and 50mass%, metastable beta+alpha double prime+omega structure at a Ta content of 60mass%, and matastable beta+omega structure at a Ta content more than 60mass%.
