Preparation And Properties Of Porous Ti-Mo Alloys

ABSTRACT:Porous Ti-Mo alloys were fabricated by powder sintering approach with Ti, TiH2and Mo powders (n(Ti): n(TiH2)=4:1). Spherical-like (NH2)2CO powders were used as the pore forming agent. The effects of different parameters on phase constituents, relative density and mechanical property of Ti-Mo alloys were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical property test methods. The results showed that:1) For Ti-14Mo alloys, increase of sintering temperature and sintering time promotes α→β phase transition and improves the relative density. The flexural strength of Ti-14Mo alloys reaches the maximum value after sintered at1200℃while the elastic modulus increases gradually with augment of sintering temperature. The maximum value of flexural strength and the minimum value of elastic modulus are achieved after sintered for5h. Compared with the flexural strength, the elastic modulus is less sensitive to the changes of sintering temperature and sintering time.2) Mo content affects α→β phase transition and the relative density of Ti-Mo alloys. The increase of Mo content facilitates the growth of β-Ti phase and makes the relative density augment. When Mo content is greater than10wt.%, near (3titanium alloy can be achieved. The flexural strength and elastic modulus are adjusted through controlling the composition ratio of Ti-Mo alloys. The comprehensive mechanical property of Ti-14Mo alloys is better than the others.3) The phase constituents of the sintered porous Ti-14Mo alloys are insensitive to the addition of (NH2)2CO. By adding space-holder of (NH2)2CO powders, the relative density, pore characteristics and mechanical properties can be regulated. With the linear increase of the adding amount of (NH2)2CO powders, the relative density reduces lineally. The fracture mechanism of porous Ti-14Mo alloys is the integration of brittle and ductile rupture.4) With adding15-30wt.%(NH2)2CO, the interconnected pore structure, relative density (36.37-61.60%), flexural strength (109.10-220.77MPa) and elastic modulus (17.06-37.96GPa) of porous Ti-14Mo alloys sintered at1200℃for5h match those of cancellous bone. Porous Ti-14Mo alloys after alkali-heat treatment and SBF soaking have good biocompatibility.