Two-dimensional Numerical Simulation Of Materials Surface Modification By High Current Pulsed Electron Beam (HCPEB)

Based on pure Aluminum, this dissertation focuses on numerical simulation and analysis of materials surface modification by High Current Pulsed Electron Beam (HCPEB). First, non-linear and non-equilibrium thermodynamic-mechanical equations are used to fully describe dynamic process induced by HCPEB bombardment, such as the transient temperature field and the coupled temperature-dynamic thermal stress field. Specially, quasi-static stress, thermo elastic stress. The axisymmetric physical and mathematic model of temperature field and thermal stress field are established, then make use of obviously limited differential method to disperse them and to simulate two-dimensional temperature field. We gain the correlative distributing of temperature field with radial and axial.In the temperature field simulation, the method of columniform materials' thermal fountain is advanced. Following assumptions and approximations are taken into account by HCPEB of 28KV, 0.8μs and 3~4.5J/cm~2: temporal functions of pulsed voltage and power are fitted with experimentally measured data, phase transition related physical parameters such as the specific heat capacity and heat conductivity etc. are treated temperature-dependently, and the latent heat is also compensated with temperature. These numerical simulations are carried out for Aluminum to reveal the temperature distributing in the samples, which provides quantitative information of melting layer thickness (2μm) and the first time of melting (0.58μs).They also gain the experimental results, the melting layer thickness is 1.4μm. Comparing with the experimental results, stimulant results and experimental results and both are consistent on the whole.In addition, the dispersive relation and corresponding physical variable from the model of thermal stress wave is deduced. These results give transmitted and evolutive process of thermal stress wave on material.