强流脉冲电子束表面改性的物理模型及数值模拟

Physical model and numerical simulation of intense pulsed electron beam surface modification

推导出了强流脉冲电子束处理过程的应力场方程,利用数值模拟,得到了温度场和应力场的分布曲线,分别给出了熔化深度、升降温的速率及温度梯度的大小,准静态应力和热应力波的幅值、应力波的传播及反射过程,利用数值模拟结果对实验中观察到的实验现象熔化深度、材料表层及次表层数微米范围内组织结构的变化及数百微米的硬度提高等给出了解释。

A one-dimension temperature and stress model is proposed based on the beam-target interaction process and thermal-elastic theory for the intense pulsed electron beam treatment. The temperature and stress profiles are derived by the numerical simulation. According to the simulation, the melted layer is about 2000 nm in depth, the rate of rapid heating and cooling reaches 108-109 K/s, the amplitude of quasi-static thermal stress is about several hundreds MPa, the vibratory frequency of thermal stress wave is about 106-108 Hz. The simulation explains satisfactorily the observed experimental phenomena as the surface melting depth and the depth distribution of microhardness.