Tensile properties of microstructure-controlled TiB whisker reinforced Ti matrix composites

摘要

Titanium boride (TiB) whisker reinforced Titanium (Ti) alloy matrix (Ti-TiB) composites have attracted attention as the aerospace materials with their high specific mechanical properties for long time. Furthermore, TiB whiskers are chemically stable in the Ti alloys and it seems that the slight difference in the thermal expansion coefficient between TiB and Ti allows a remaining thermal stress inside the TiB whiskers to be dispersed within Ti-TiB composite. Therefore, it is likely that TiB can be a prime candidate for the reinforcement of TMCs. However, it has been reported that the TiB whiskers addition causes the embrittlement of Ti alloys, while Ti-TiB composites have outstanding tensile strengths in previous studies. We observed that TiB whiskers were firstly fractured in Ti-6Al-4V alloy matrix under tensile load, and it was seemed this fracture caused the embrittlement of Ti alloys. In this study, using Ti particles with a diameter of100 ~150μm, TiB whiskers were dispersed around Ti particles and formed TiB network inside Ti matrix. It is likely that this microstructure allows to improve both of their tensile strength and fracture elongation. We evaluated the tensile properties of Ti-TiB composite with TiB network inside Ti matrix.