Effect of Y Alloying on Microstructure and Mechanical Properties of Ti-48Al Alloy

The effects of Y content (ranged from 0.1 at.% to 2.0 at.%) on the microstructure evolution and mechanical properties of Ti-48Al (at.%) alloy were investigated. The addition of Y can significantly refine the microstructure. The grain size is decreased with increasing Y content. The microhardness of Ti-48Al-xY (at.%) is increased with increasing Y content because of the volume fraction increment of Al3Y and Y2O3 with higher hardness. When the Y content increased to 1.0 at.%, the microhardness of the Ti-48Al-xY (at.%) alloys tends to be stable. With the increase of Y content, the compression strength of Ti-48Al-xY (at.%) alloys is increased first and then decreased. The Ti-48Al-0.5Y (at.%) alloy exhibits the best compression strength (2229 MPa), which is 15% higher than that of Ti-48Al (at.%) alloy. The fracture mechanism of the alloy is brittle fracture. The fracture modes are mainly translamellar and interlamellar fracture.