Tensile strength and impact toughness of gallium-bearing near-α titanium alloys

The present study aims to quantify the properties of Ga-bearing near- α titanium alloys in order to aid the future design of new compositions with Ga addition. The effect of different amounts of Sn and Ga, with an almost constant value in the Al equivalent without the formation of α 2 phase, on microstructure, tensile strength and Charpy impact toughness was investigated at room temperature and 650 °C. The microstructures after forging, hot rolling and heat treatment showed a bimodal structure. Increasing Ga decreased the 0.2% proof stress at 650 °C. However, these alloys showed similar impact value at room temperature which was about 40 J/cm². Increasing the amount of Ga increased the volume fraction of the equiaxed α phase. The amount of Ga had only a minor effect on grain size, misorientation angles and grain aspect ratios of the alloy. However, Ga addition had a strong influence on the evolution of texture. Formation of <10-10> and <10-11> || normal direction (ND) fibers were observed in the Ga added samples, in addition to <0001> || ND fiber with a weak <10-11> || ND fiber. The Ga-free sample contained a strong <0001> || ND fiber. Other fibers were not observed.