316L不锈钢基材防氚渗透Al2O3涂层残余热应力分析

在聚变堆防氚渗透第一壁制备过程中,Al2O3涂层与316 L不锈钢基体间由于材料热膨胀系数的差异容易产生裂纹.本文利用有限元方法研究了AL2O3/316 L涂层制备过程中的残余应力的分布.结果表明在界面等区域存在严重的应力集中;涂层厚度、孔隙率大小以及涂层是否致密对残余应力水平有很大影响.涂层内部关键区域的残余应力水平,随着涂层厚度增加而增加;孔隙率不同对界面的残余应力分布趋势没有明显影响,但对应力值却有很大影响,孔隙率增大涂层残余应力最大值下降;相同厚度情况下致密Al2O3涂层所受压应力远大于多孔Al2O3涂层承受的残余应力.

Residual stresses of Al2O3 tritium penetration barrier on 316 L stainless steel substrate

During the preparation of the first barrier of nuclear fusion reactor, it was found that cracks were easily engendered at the interface between Al_2O_3 coatings and the substrate of 316L because of the mismatch of their thermal expansion coefficients. The distributions of residual stresses in Al_2O_3/316 L coatings were simulated by finite element analysis. The results show that a remarkable stress concentration at the edge of some interface. The thickness,the porosity and the dense of the coatings play an important role in the level of residual stresses. FEA molding results indicate that the levels of residual stresses at the critical interface regions increase with the increase of the thickness. The porosity has no effect on the distribution of the interracial residual stress, but it affects the value of the stresses greatly; The levels of residual stresses decrease with the increase of the porosity. The calculated thermal stresses in dense Al_2O_3 coatings were much larger than those in porous Al_2O_3 coatings when the thickness of both Al_2O_3 coatings were the same.