强流脉冲电子束诱发温度场及表面熔坑的形成

在强流脉冲电子束表面改性实验的基础上，通过数值计算方法对铝和钢的温度场和熔化过程 进行模拟，给出了最先熔化的位置、形成熔孔的最大深度以及表面层下熔化的最大深度. 通 过铝和钢的熔化潜热温度补偿的数值模拟结果和实验结果的对比，揭示了亚表层率先升温及 熔化从而通过表层向外喷发的熔坑的形成机制. 关键词： 强流脉冲电子束 热传导 数值模拟 熔孔

Temperature field and formation of crater on the surface induced by high curren t pulsed electron beam bombardment

The present paper aims at revealing the formation mechanism of craters on the surface of metals produced by the bombardment of a high-current pulsed electron beam. Based on experimental investigations and a physical model, the temperature field and melting process are simulated for Al and two kinds of steels. The star ting melting positions, largest crater depths, and melting layer thicknesses are obtained, which agree satisfactorily with experimentally observed values. It is confirmed that temperature rises faster at a sublayer instead of on the extreme surface due to the maximum energy deposition located at about 1/3 of the total penetration depth of the beam. Such a special sublayer heating and melting mode causes eruptions of the sublayer liquid through the outer surface and produces t he typical surface crater morphology.