G0400305 機械的特性に及ぼすTiB強化Ti-6Al-4V合金のマトリックス粉末の粒径と形状の影響

Abstract

It has been reported that the mechanical properties of titanium matrix composites depended on titanium particle shape and size. In this study, three types of Ti-6Al-4V matrix powders were used: hydride-dehydride (HDH) powders with particle sizes of <45 μm and <25 μm and gas-atomized (GA) powder with a particle diameter of 45 μm. TiB_2 powder with an average particle size of 1.81 μm was used as a reinforcement. TiB-reinforced Ti-6Al-4V alloys were prepared by SPS. Mechanical properties of composites composed of powders with different particle shape and sizes were investigated. As a result, the mechanical properties of the composites with HDH powders depended on the particle size. The TiB whiskers were uniformly distributed in the composites with smaller Ti particle. In the composites with HDH or GA of particle size of 45 μm, their mechanical properties depended on the particle size. The tensile strength and Vickers microhardness of the composite with HDH powder were higher than those of the composite with GA powder. On the other hand, the tensile strengths of the GA composites with the GA powder exhibited higher values at a high volume fraction of TiB.