In order to clarify the effect of additive elements on mechanical properties in solid solution strengthened titanium alloy, pure titanium (CP-Ti), Ti-1 mass% Al (Ti-1Al) and Ti-1 mass% Cu (Ti-lCu) alloys were prepared. The tensile tests at various temperature and the microstructure observation were carried out. In this study, it was found that the tensile strength and the 0.2% proof stress of Ti-1Al and Ti-1Cu were higher than those of CP-Ti and the total elongation of Ti-iCu was higher than that of Ti-1Al. The 0.2% proof stress of Ti-1Cu from 100℃ to 500℃ was highest among them. A lot of deformation twins were observed in CP-Ti and Ti-1Cu deformed at room temperature. From these results, the increase of the tensile strength and the total elongation are considered to be due to the number of twin in Ti-1Cu.
