铀表面铝镀层热应力的有限元分析

对铀表面磁控溅射沉积铝镀层的热应力进行了热弹塑性有限元分析。结果表明：镀层内的热应力较大,达到铝的屈服强度,镀层界面两侧存在明显应力梯度,试样侧边存在由于边缘效应引起的应力分布不均匀性,至侧边约4倍镀层厚度处,应力分布不均匀性逐渐消失；沉积温度升高,界面塑性应变明显增大,镀层弹性模量和泊松比对镀层界面热应力和塑性应变的影响较小,而屈服强度的影响较大,减薄镀层厚度有利于改善镀层界面的热应力和塑性应变。

Thermal Stress Analysis in Al Coating on Uranium Substrate by Finite Element Method

The thermal stress in magnetron sputtered Al coating on uranium substrate was studied by thermal elastic plastic finite element method (FEM).The thermal stress in A1 coating was rather lage and reached the yield strength of A1.A large stress gradient existed at the interface between A1 coating and uranium substrate.The end effect resulted in an uneven thermal stress distribution at the free side of specimen,which vanished gradually at the position of about 4 times of the coating thickness from the free side of specimen.The effects of deposition temperature,mechanical properties and coating thickness on thermal stress and plastic strain at the interface were also investigated.The plastic strain at the interface increased with increasing the deposition temperature,hut there were small effects of Young's modulus and Poisson's ratio on the thermal stress and plastic strain at the interface, and large effects of the yield strength of A1 coating on them.Decreasing the thickness of Al coating was helpful to decrease the thermal stress and plastic strain at the interface of Al coating.