高应变率下不同初始相变温度NiTi合金的力学响应  

Mechanical response of NiTi alloys with different initial phase transition temperatures at high strain rates

作　　者：张旭平[1] 董金磊 吕超 罗斌强[1] 王桂吉[1] 谭福利[1] 赵剑衡 ZHANG Xuping;DONG Jinlei;LYU Chao;LUO Binqiang;WANG Guiji;TAN Fuli;ZHAO Jianheng(Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621999,Sichuan,China;Institute of Applied Electronics,China Academy of Engineering Physics,Mianyang 621999,Sichuan,China)

机构地区：[1]中国工程物理研究院流体物理研究所,四川绵阳621999 [2]中国工程物理研究院应用电子学研究所,四川绵阳621999

出　　处：《爆炸与冲击》2024年第5期99-107,共9页Explosion and Shock Waves

基　　金：国家自然科学基金(12002327,12272364,11972031)。

摘　　要：为获得高应变率下不同初始相变温度NiTi合金的屈服应力等基本物理特性和力学响应规律,采用10^(−3)s^(−1)应变率下准静态压缩与拉伸、10^(5)s^(−1)应变率下准等熵压缩及10^(7)s^(−1)应变率下冲击加载实现跨量级的不同应变率加载,高应变率加载实验中通过控制样品初始温度实现不同初始相态NiTi合金的力学响应测量。结果显示,初始马氏体相和初始奥氏体相NiTi合金的准静态加载应力-应变曲线中均出现2次模量变化,初始马氏体相中的模量变化由晶体重定向和马氏体相塑性变形引起,初始奥氏体相中的模量变化由马氏体相变和相变后塑性变形引起。准等熵加载下,初始马氏体相NiTi合金的Lagrangian声速随粒子速度增大而增大,未观察到间断等非线性变化;而初始奥氏体相中声速曲线存在间断,声速由初始横波值间断减小至体波声速后再随粒子速度线性增大。冲击实验中,初始马氏体相NiTi合金后自由面速度约34 m/s处出现双波结构,而将样品初始温度升至402 K后再冲击加载,则在约100 m/s处出现双波结构,二者速度曲线拐点分别由马氏体相弹塑性屈服和奥氏体相塑性屈服引起;在初始奥氏体相NiTi合金冲击实验中,在样品后自由面速度达到220~260 m/s时才出现显著的奥氏体相弹塑性转变。随着应变率从约105 s^(−1)升高至10^(7) s^(−1),相同组分奥氏体相NiTi合金的弹性极限由约2 GPa增大至约4 GPa,10^(7) s^(−1)应变率下,随着初始样品温度升至402 K,弹性极限降至1.7 GPa,表明NiTi合金的弹性极限存在显著的温度和应变率效应。In order to obtain the physical and mechanical properties of NiTi alloys with different initial phase transition temperatures under high strain rates,the responses of NiTi alloys with different initial phase transition temperatures were systematically studied under quasi-static compression and tension at strain rate 10−3 s^(−1),quasi-isentropic compression at strain rate 105 s^(−1),and shock compression at strain rate 10^(7) s^(−1).Dog-bone specimens and cylindrical rod specimens were used in the quasi-static tension and compression experiments,respectively.A series of quasi-isentropic compression and planar shock wave compression experiments were performed by using the pulsed power generator CQ-4,which can deliver pulsed currents with peak values of 3–4 MA and a rise time of 470–600 ns to short circuit loads.Velocities were measured by a photonic Doppler velocimetry (PDV) system with accuracies of 1%. The quasi-static loading stress-strain curves showed twice modulus changes for both the initial martensitic and initial austenitic NiTi alloys. The modulus changes were caused by crystal reorientation and plastic deformation of the martensitic NiTi alloy. In experiments of the initial austenitic phase, the modulus changes were caused by martensitic phase transition and plastic deformation after phase change. The Lagrangian sound speed increased continuously with the particle velocity for the initial martensitic NiTi alloy under quasi-isentropic loading. However, there are discontinuities in the sound speed curves for the initial austenite phase. The sound speed decreases intermittently from the transverse wave speed to the longitudinal wave speed and then increases linearly with the particle velocity. In shock experiments of initial martensitic NiTi alloy, a double-wave structure appeared at the free surface velocity of about 34 and 100 m/s for the initial sample temperature of 302 and 402 K, respectively. The martensite-austenite phase transition occurred during sample heating of the initial martensiti

关 键 词：NITI合金 奥氏体-马氏体相变 相变温度 高应变率 弹性极限 

分 类 号：O346.4[理学—固体力学]