陶瓷-可伐合金钎焊件残余应力分析

Analysis of residual stress in ceramic-Kovar alloy brazing

钎焊冷却中产生的热应力是引起钎焊件失效的重要原因。本文采用有限元法对陶瓷-可伐合金钎焊件残余应力进行三维数值仿真,模拟了不同时刻的温度场和残余应力的分布。数值模型考虑了热传导、炉膛壁的辐射、炉膛内的对流、钎料的熔化凝固等对温度场的影响。结果表明,靠近钎缝位置残余应力最大;陶瓷一侧的残余应力数值上比可伐合金一侧的大;陶瓷边缘位置垂直钎缝方向的残余拉应力最大;增加钎料厚度和带有圆弧倒角均有益于降低试样的残余应力。

The thermal stress caused by brazing was an important reason for the failure of the solder. In this paper,the finite element method was used to simulate the residual stress of ceramic-Kovar alloy brazing, and the distribution of temperature field and residual stress at different time was simulated. The heat conduction, the radiation of the furnace wall, the convection in the furnace, the influence of the melting and solidification of the solder on the temperature field were considered in the numerical model. The simulation results showed that the maximum residual stress was close to the weld, the residual stress of ceramic was larger than that of alloy, the residual tensile stress in the vertical direction of the ceramic was the largest. Increasing the solder thickness and arc chamfer were beneficial to reduce the residual stress.