【摘要】 采用水冷铜坩埚磁悬浮真空熔炼炉制备了（TiZrHf）₅₀Ni₃₀Cu_20-xCo_x（x=2,4,6,at%）高熵高温形状记忆合金，并研究了Co含量对其微观组织和力学性能的影响。结果表明，随着Co含量增加，合金晶粒尺寸减小。合金在铸态下主要由B19′和少量B2相组成，断口组织富含B19′相，而B2相几乎消失。增加Co含量和缩小试样尺寸（d）显著提升了合金的抗压强度和塑性，在d=2 mm时，（TiZrHf）₅₀Ni₃₀Cu₁₄Co₆合金表现出最佳综合力学性能，抗压强度为2142.39±1.8 MPa，塑性为17.31±0.3%。压缩循环试验显示，随着压缩应变增加，（TiZrHf）₅₀Ni₃₀Cu₁₄Co₆合金的残余应变增大，但回复能力减弱。合金的超弹性回复能力不断增强，超弹性回复率从1.36%增至2.12%，残余应变率从1.79%增至5.52%，弹性回复率从3.86%增至7.36%，总回复率从74.48%降至63.20%。更多还原

【Abstract】 (TiZrHf)₅₀Ni₃₀Cu_20-xCo_x（x=2, 4, 6, at%） high-entropy high-temperature shape memory alloys were fabricated by watercooled copper crucible in a magnetic levitation vacuum melting furnace, and the effects of Co content on microstructure and mechanical properties were investigated. The results indicate that the grain size of the alloy decreases with increasing the Co content. In the as-cast state, the alloy consists primarily of the B19′ phase, with a trace of B2 phase. The fracture morphology is predominantly composed of the B19′ phase, whereas the B2 phase is nearly absent. Increasing the Co content or reducing the sample dimensions（d） markedly enhance the compressive strength and ductility of the alloy. When d=2 mm, the（TiZrHf）₅₀Ni₃₀Cu₁₄Co₆ alloy demonstrates the optimal mechanical properties, achieving a compressive strength of 2142.39±1.8 MPa and a plasticity of 17.31±0.3%. The compressive cyclic test shows that with increasing the compressive strain, the residual strain of the（TiZrHf）₅₀Ni₃₀Cu₁₄Co₆ alloy increases while the recovery ability declines. The superelastic recovery capability of the alloy is continuously enhanced. The superelastic recovery rate increases from 1.36% to 2.12%, the residual strain rate rises from 1.79% to 5.52%, the elastic recovery rate ascends from 3.86% to 7.36%, while the total recovery rate declines from 74.48% to 63.20%.更多还原