The addition of ternary alloying elements Cu and Fe on the hot workability of binary NiTi SMA is assessed using the processing maps approach. Uniaxial compression test data obtained in the temperature, T, range 800–1050 °C and strain rate, $\dot{\mathrm{\epsilon }}$, of 10⁻³ – 10⁺¹ s⁻¹ were utilized to construct power dissipation, instability and strain rate sensitivity maps at true strain, ε = 0.5. These maps and complementary microstructural analyses of the deformed specimens were used to identify various deformation mechanisms operating in different T-$\dot{\mathrm{\epsilon }}$ regimes. Based on the processing maps, three stable domains for processing were identified with Domain-2 occurring at higher T and intermediate $\dot{\mathrm{\epsilon }}$ with power dissipation efficiency of 30–45% being the optimum for thermo-mechanical processing. The addition of Cu in NiTi SMA improves its hot workability through enlarging stable domains for processing whereas Fe addition shrinks it. Microstructural analysis indicates occurrence of dynamic recrystallization (DRX) in NiTi, NiTiFe and dynamic recovery (DRV) in NiTiCu as the dominating deformation mechanism in Domain-2. Sluggish DRX kinetics in NiTiCu SMA in Domain-2 is related to its higher deformation resistance and higher critical stress required for the onset of DRX vis-à-vis NiTi, NiTiFe SMAs. Instability maps corroborated through microstructural analysis showed instability in the form of flow localization.

使用加工图方法评估在二元NiTi SMA的热加工性上添加三元合金元素Cu和Fe。在温度T，温度范围800–1050°C和应变率下获得的单轴压缩测试数据，$\dot{\mathrm{\epsilon }}$10 ^-3 – 10 ⁺¹ s ^-1中的，用于构建真实应变ε  = 0.5时的功耗，不稳定性和应变率敏感性图。这些图和变形标本的互补微结构分析被用来确定在不同的T-下运行的各种变形机制。$\dot{\mathrm{\epsilon }}$政权。根据加工图，确定了三个稳定的加工域，其中Domain-2出现在较高的T和中等$\dot{\mathrm{\epsilon }}$热机械处理的最佳功耗效率为30–45％。NiTi SMA中添加Cu可通过扩大稳定的加工区域来提高其热加工性，而Fe的添加则会使其收缩。显微组织分析表明，NiTi，NiTiFe中发生动态再结晶（DRX），NiTiCu中发生动态恢复（DRV），这是Domain-2中主要的变形机制。域2的NiTiCu SMA中DRX动力学缓慢，与DRX相对于NiTi，NiTiFe SMA出现所需的更高的抗变形性和更高的临界应力有关。通过微结构分析证实的不稳定性图以流动局部化的形式显示了不稳定性。