爆炸焊接记忆合金Ni50Ti50与Cu界面扩散机理的研究

Research on the Mechanism of Explosive Welding Interface Diffusion Between Memory Alloy Ni50Ti50 and Cu

摘要:

为了揭示焊接界面细观尺度扩散特征，采用内嵌入势函数（EAM势）通过对形状记忆合金Ni50Ti50和Cu进行爆炸焊接界面分子动力学数值模拟，同时结合SEM、EDX测试方法对爆炸焊接界面微细观形貌及物理特征实验分析，研究结果表明以记忆合金Ni50Ti50与Cu在采用uz= -1500 m/s, ux= 700 m/s冲击碰撞工况下，体系的压强震荡逐渐变小，120ps以后已经趋于平衡，体系的温度稳定在1350K左右，而压强稳定在28GPa左右; 在扩散层两侧Cu的原子浓度一直维持在5%左右，Ni和Ti的原子浓度在47%上下波动，界面扩散层厚度在1.03μm~1.45μm的范围内；实验结果采用SEM、EDS微观分析验证了获得焊接界面扩散层厚度约为1.56μm，基本与计算结果相一致。

Abstract:

This paper mainly adopted a hybrid molecular dynamics simulation method with the classical diffusion theory, in order to reveal the micro-scale diffusion characteristics of the welding interface, the molecular dynamics simulation of the explosive welding interface of shape memory alloy Ni50Ti50 and Cu was carried out by means of the embedded potential function (EAM potential). The micro-morphology and physical characteristics of the explosive welding interface were analyzed by means of SEM and EDX. The pressure oscillation of Ni50Ti50-Cu alloy system becomes smaller and smaller under the impact condition of uz=1500 m/s and ux=700 m/s. The temperature of the system is about 1350 K and the pressure is about 28GPa after 120ps. The atomic concentration of Cu on both sides of the diffusion layer is about 5% and that of Ni and Ti is about 5%. The interfacial diffusion layer thickness ranged from 1.03 to 1.45um. The thickness of the interfacial diffusion layer was about 1.56um, which was verified to the results of the SEM and EDS.