冲击载荷下Ni_(52)Ti_(48)合金的微观响应特性  

Micro-Scale Response Characteristics of Ni_(52)Ti_(48) Alloy under Shock Loading

作　　者：吕超[1,2] 张旭平 王桂吉[2] 罗斌强[2] 罗宁[3] 吴恒安[1] 谭福利[2] 赵剑衡[4] 刘仓理 孙承纬[2] LÜChao;ZHANG Xuping;WANG Guiji;LUO Binqiang;LUO Ning;WU Heng’an;TAN Fuli;ZHAO Jianheng;LIU Cangli;SUN Chengwei(CAS Key Laboratory of Mechanical Behavior and Design of Materials,Department of Modern Mechanics,University of Science and Technology of China,Hefei 230027,Anhui,China;Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621999,Sichuan,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,Jiangsu,China;Institute of Applied Electronics,China Academy of Engineering Physics,Mianyang 621999,Sichuan,China;China Academy of Engineering Physics,Mianyang 621999,Sichuan,China)

机构地区：[1]中国科学技术大学近代力学系,中国科学院材料力学行为和设计重点实验室,安徽合肥230027 [2]中国工程物理研究院流体物理研究所,四川绵阳621999 [3]中国矿业大学力学与建筑工程学院深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [4]中国工程物理研究院应用电子学研究所,四川绵阳621999 [5]中国工程物理研究院,四川绵阳621999

出　　处：《高压物理学报》2021年第4期125-138,共14页Chinese Journal of High Pressure Physics

基　　金：国家自然科学基金(11972031,12002327)。

摘　　要：为了了解近等原子比NiTi合金在高压高应变率下的动态变形行为和微结构演化特性及机制,采用实验和分子动力学模拟方法,开展了NiTi冲击压缩和冲击加-卸载拉伸研究。在实验方面,基于大电流脉冲功率CQ-4装置,利用电磁驱动高速飞片,结合动量陷阱和软回收实验技术,开展了冲击压缩与冲击加-卸载拉伸作用下Ni_(52)Ti_(48)合金的动态变形特性研究,借助X射线衍射和电子背散射衍射显微技术,对回收Ni_(52)Ti_(48)合金样品进行微结构特征观察和分析。结果表明,Ni_(52)Ti_(48)在冲击压缩和拉伸下都没有发生马氏体相变,主要变形方式为位错滑移等塑性变形。在分子动力学数值模拟方面,计算结果很好地反映了实验观察到的微结构特征,计算得到的不同初始环境温度和不同冲击速度下Ni_(52)Ti_(48)合金的层裂强度表现出明显的卸载拉伸应变率效应。相关工作加深了对Ni_(52)Ti_(48)合金在高压高应变率下变形行为的理解和认识,为其在极端环境下的安全服役提供了参考。Experiments and molecular dynamics simulations were carried out to understand the dynamic deformation behavior,microstructure evolution characteristics and mechanism of near equiatomic NiTi alloy at high pressures and high strain rates.In the experiments,the dynamic deformation characteristics of Ni_(52)Ti_(48) alloy under shock compression and shock loading-unloading were studied by electromagnetically driven high-velocity flyer plate,momentum trapping and soft recovery experimental techniques based on high current pulse power device CQ-4.By means of X-ray diffraction and electron backscattered diffraction,the microstructure characteristics of Ni_(52)Ti_(48) alloy were analyzed,the results show that there is no martensitic transformation in Ni_(52)Ti_(48) alloy under shock compression and tension,and the main deformation mode is plastic deformation such as dislocation slip.Moreover,the microstructure evolution characteristics and deformation mechanism of Ni_(52)Ti_(48) alloy under shock compression were studied by non-equilibrium molecular dynamics simulations,and the calculated results well reflect the microstructure characteristics observed in the experiment.Meanwhile,the spall strength of Ni_(52)Ti_(48) alloy at different initial ambient temperatures was calculated,and the results show obvious unloading strain rate effect.The related work has deepened the understanding of the deformation behavior of Ni_(52)Ti_(48) alloy at high pressures and high strain rates,and provided a reference for its safe service in extreme environment.

关 键 词：NITI 形状记忆合金 动态响应 微结构演化 塑性变形机制 层裂强度 

分 类 号：O521.2[理学—高压高温物理] O347[理学—物理]