Study of microstructure evolution and properties of ZrTi/GH4169 alloys prepared by low-temperature sintering of SPS

This paper proposes a method involving low-temperature SPS for preparing ZrTi/GH4169 alloy blanks. The addition of GH4169 alloy significantly reduces the sintering temperature of ZrTi alloy. The Zr30-Ti62-Ni8 ratio was used to obtain equiaxed grains of ZrTi alloy through sintering at 1000 °C, and billets with excellent strength and plasticity under high-temperature deformation were obtained by sintering at 1100 °C. In the sintering temperature range from 1000 °C to 1200 °C, while both α-phase and Zr₂(Fe,Ni) phase size increased with the sintering temperature, the amount of increase was different. Specifically, the α-phase in the alloy blanks sintered at 1100 °C was fine and reticulated, whereas that sintered at 1200 °C developed into a slatted structure. Strengthening mechanism analysis showed that the strength and plasticity of the 1100 °C sintered blanks were excellent, especially because of the effect of the reticulated α-phase and Zr₂(Fe,Ni) phase. Furthermore, the high density of the phase interface hindered dislocation movement and inhibited stress concentration. In particular, the Zr₂(Fe,Ni) phase distributed along the β-phase grain boundaries and around the α-phase in the grain acted as a nail, and it could inhibit grain growth and increase resistance to dislocation motion. The weaker β-phase weave and lower defect density also contributed to the superior material properties of the 1100 °C sintered blanks.