陶瓷-金属钎焊接头残余应力的数值分析

采用热弹塑性有限元方法，在考虑了材料性能参数随温度变化和界面反应层的情况下，计算了陶瓷／金属钎焊接头残余应力的大小和分布。通过计算发现：陶瓷／金属接头在冷却过程中产生的径向应力和剪应力对接头的影响较小。而在陶瓷表面的边缘接近焊缝的位置产生了最大的轴向拉应力，它影响接头的载荷承受能力，并且由于40Cr的屈服强度比45钢的高，计算出的Si3N4／40Cr接头的应力峰值比Si3N4／45钢的高。陶瓷／钎料和陶瓷／金属的界面反应层虽然薄，但它也是影响陶瓷／金属接头残余应力大小和分布的一个重要因素。另外，选择合适的钎料层、中问层和钎焊压力都可以有效地减小残余应力的峰值。

Numerical analysis of residual stress in ceramics/metal brazed joints

The residual stress in ceramics/metal joints was calculat-ed by thermal-elastic-plastic finite element method in this paper. The in-fluence of temperature on the material properties and the interface reactionlayer was taken into account. The radial stress and shearing stress had a little influence on the joints, but a peak axial tensile stress which influ-enced on load-bearing capacity of joints occurred at the ceramic surfaceson the edges. The maximum of residual stress of Si_3N_4/40Cr brazed jointsis higher than that of Si_3N_4/45 steel joints, because yield strength of 40Crsteel is higher than that of 45 steel. Though the reaction layers of inter-faces are thin, they are important factors which influence on residualstress. In addition,the peak residual stress can be reduced by appropriatefiller metal, interlayer and brazing pressure.