Study on Microstructure and Properties of Ti_100-x(Gd₂Fe₁₇)_x Alloys Fabricated by Vacuum Arc Melting

This study aims to investigate the effect of Gd₂Fe₁₇ content on the microstructure and properties of Ti_100-x(Gd₂Fe₁₇)_x alloys. This series of the alloys was fabricated using vacuum arc melting technology. The effects of Gd₂Fe₁₇ content on the microstructure and properties of the alloys were investigated by means of X-ray diffraction, scanning electron microscopy, differential thermal dilatometry and other characterization mothods. The results demonstrate that the alloys consist of β-Ti matrix and Gd-Fe intermetallic compounds(IMCs) precipitated phases. With increasing Gd₂Fe₁₇ content, the volume fraction of Gd-Fe IMCs in the alloys increases gradually, which leads to a continuous rise in fracture strength, and an initial increase followed by a decrease in elongation. Conversely, a gradual reduction in thermal expansion coefficient. Among all the alloys, Ti_100-x(Gd₂Fe₁₇)_x exhibits the optimal comprehensive performance, with a fracture strength of 774 MPa, an elongation of 7.3%, and a thermal expansion coefficient of 8.5×10^-6/℃. Compared with the Ti₉₈(Gd₂Fe₁₇)2 alloy, its fracture strength and elongation are increased by 26.5% and 40.4%, respectively, whereas its thermal expansion coefficient is decreased by 4.5%. The excellent comprehensive performance of the alloy is attributed to the strengthening and thermal expansion compensation effects of the fine, low-expansion Gd-Fe IMCs that are uniformly and dispersively distributed in the matrix.