Ti-Ni二元形状记忆合金的相变温度较低，限制了其在高温领域的应用，添加Hf元素可有效提升相变温度，但也会导致合金可变形性降低。因此，需要研究三元Ti-Ni-Hf高温形状合金热变形行为，确定热加工窗口。本工作采用真空感应熔炼制备Ti₃₀Ni₅₀Hf₂₀高温形状记忆合金，利用OM和Gleeble-3800热模拟试验机等，对Ti₃₀Ni₅₀Hf₂₀高温形状记忆合金的热变形行为进行了研究，变形温度为700、800和900 ℃，应变速率为0.01、0.1、1和10 s^-1。结果表明，Ti₃₀Ni₅₀Hf₂₀高温形状记忆合金在高温热变形过程中具有负温度、正应变敏感性，其流变应力随应变速率增加而增大，随变形温度升高而减小，且随变形温度升高再结晶现象增强；利用Arrhenius热变形表达式建立了Ti₃₀Ni₅₀Hf₂₀高温形状记忆合金热加工的本构方程，其应变激活能为527.447 kJ/mol，根据本构方程计算得到的峰值应力理论值与实验值相吻合；根据Ti₃₀Ni₅₀Hf₂₀高温形状记忆合金的动态模型建立其热加工图，确定其最佳热变形加工参数为变形温度880~900 ℃，应变速率0.01~0.04 s^-1。

The application of Ti-Ni binary alloy at high temperatures is hindered by its low phase transition temperature. To enhance this transition temperature, researchers have explored the addition of metal Hf to Ti-Ni alloy. However, Ti-Ni-Hf high-temperature shape memory alloy exhibits brittleness and lacks favorable thermal deformation characteristics. Thus, a comprehensive investigation of its thermal deformation behavior is essential. During the hot working process, the material undergoes shape and microstructural changes, which are influenced by various processing factors. Consequently, optimizing processing parameters, including temperature, strain, and strain rate, is crucial for producing defect-free components with the desired microstructure. To optimize the hot working technology, single-pass compression tests on a Gleeble-3800 thermo-simulation machine were conducted and the hot deformation behavior and workability of the high-temperature shape memory alloy Ti₃₀Ni₅₀Hf₂₀ were explored. These tests covered a temperature range of 700-900 ^oC and a strain rate range of 0.01-10 s^-1. Flow stress-strain curves for Ti₃₀Ni₅₀Hf₂₀ under different deformation conditions were generated and the evolution of the alloy's microstructure at varying deformation temperatures under a strain rate of 0.01 s^-1, as well as at a deformation temperature of 900 ^oC with different deformation rates were examined. Utilizing a dynamic material model, a processing diagram was constructed and the impact of process parameters on the alloy's processing performance was analyzed. The results indicate that the recrystallization of Ti₃₀Ni₅₀Hf₂₀ high-temperature shape memory alloy increases with the deformation temperature. This alloy exhibits negative temperature sensitivity and positive strain sensitivity, with flow stress increasing as the strain rate rises and decreasing with higher deformation temperatures. A constitutive equation for Ti₃₀Ni₅₀Hf₂₀ high-temperature shape memory alloy during hot working is established, employing the Arrhenius hot deformation equation. The calculated strain activation energy was determined to be 527.447 kJ/mol. It revealed a consistent match between the theoretical and actual peak stress values. Through the assessment of the hot working diagram, the optimal processing parameters are identified as a deformation temperature in the range of 880-900 ^oC and a strain rate of 0.01-0.04 s^-1.