Effect of Y₂O₃ on Microstructure and Mechanical Properties of Ti-3Al-5.1Cr-4Fe-0.5Mo Alloy

Ti-3Al-5.1Cr-4Fe-0.5Mo alloys with different Y₂O₃ content were fabricated using vacuum arc melting technology. The effects of Y₂O₃ content on the microstructure and mechanical properties of the alloy were investigated by means of X-ray diffraction, scanning electron microscopy, universal electronic testing machine, and other characterization techniques. The results demonstrate that the alloys consist of α-Ti matrix and Y₂O₃ precipitates. With the increase of the Y₂O₃ content, the amount of micro/nano Y₂O₃ phase increases gradually, leading to an initial increase followed by a subsequent decrease in tensile strength and elongation. Among all alloys, the 0.2Y₂O₃/Ti-3Al-5.1Cr-4Fe-0.5Mo alloy achieves the optimal comprehensive properties, with the tensile strength of 987 MPa and elongation of 8.1%, increased by 24.2% and 107.7% respectively compared with the 0.1Y₂O₃/Ti-3Al-5.1Cr-4Fe-0.5Mo alloy. The excellent performance is attributed to the synergistic strengthening of intragranular and grain-boundary micro/nano Y₂O₃ and grain refinement