2017 年 58 巻 10 号 p. 1397-1403
This study was conducted to comprehensively investigate the fundamental properties of Ti-6Al-4V alloy produced by the selective laser melting (SLM) method. The examined materials were three SLM materials having different axial directions. For comparison, wrought material of Ti-6Al-4V alloy was also examined. The results showed that the densities of the SLM materials were adequately high and more than 99.9% of that of the wrought material. The SLM materials possessed a columnar microstructure extending along the building direction. This microstructure was mainly composed of the acicular α' martensite phase. Due to the generation of the fine α' phase, the static strength of the SLM materials was markedly higher than that of the wrought material although their elongation was lower. There was anisotropy in the static strength and the ductility of the SLM materials. In spite of the higher tensile strength, the fatigue strength of the SLM materials was much lower than that of the wrought material since molding defects may induce stress concentration and accelerate the generation of fatigue cracks.
