MoNbHfZrTi难熔高熵合金的动态力学性能与微观结构

Dynamic Mechanical Properties and Microstructure of MoNbHfZrTi Refractory High⁃entropy Alloy

利用分离式霍普金森压杆系统对等物质的量比MoNbHfZrTi难熔高熵合金在应变速率为1×10^(-3)~3.883×10^(3)s^(-1)时进行了压缩实验。利用场发射扫描电子显微镜观察了高熵合金试样在不同应变速率下的破坏断口微观形貌,研究了该高熵合金在不同应变速率下的变形机理。结果表明,当应变速率为1×10^(-3)~3.883×10^(3)s^(-1)时,随着应变速率的提高,MoNbHfZrTi难熔高熵合金表现出明显的正应变速率强化效应。MoNbHfZrTi难熔高熵合金在准静态压缩下的断口形貌均呈明显的准解理断裂特征,而在高应变速率压缩条件下的断裂方式是准解理断裂与韧性断裂的复合模式。

Asplit⁃Hopkinson pressure bar was used to study the dynamic mechanical properties and microstructure of equiatomic MoNbHfZrTi refractory high⁃entropy alloy under a wide range of strain rate(1×10^(-3)—3.883×10^(3) s^(-1)).The morphology of the fracture surface of the samples at various strain rates was examined by SEM.The deformation mechanism of the alloy under different strain rate was studied.The results show that MoNbHfZrTi refractory high⁃entropy alloy exhibit an obvious positive strain⁃rate strengthening effect with increasing the strain rate.The fracture morphology of MoNbHfZrTi refractory high⁃entropy alloy in quasi⁃static compression is quasi cleavage fracture characteristics,and the fracture morphology of MoNbHfZrTi refractory high⁃entropy alloy in high strain rate compression is ductile fracture and quasi cleavage fracture mixed characteristics.