铝和铝合金钎焊蓝宝石接头的残余热应力有限元分析

Analyzing residual stress in sapphire brazed joints with pure aluminum and aluminum alloy as fi ller metals

为了较为精确地了解陶瓷焊接接头内的残余热应力分布及其在不同条件下的演变规律,以蓝宝石钎焊接头为研究对象,使用有限元方法模拟了其在不同的条件下的残余热应力分布。建立了蓝宝石钎焊接头的有限元模型,考察了使用纯铝和2024铝合金作为焊缝填充金属钎焊蓝宝石的接头残余热应力分布。同时模拟了焊后热处理对2024铝合金钎焊接头的残余热应力的影响。结果表明,纯铝作为填充金属的接头残余应力较小;2024铝合金作为填充金属的接头残余应力较大,热处理后的接头残余应力降低约50%~70%。在所有的情况下,最大的残余应力都出现在焊缝平面的边缘区域而非中心区域。

To reveal the residual stress in ceramic brazed joints in a relatively qualifi ed manner, as well as its evolution pattern in different conditions, fi nite element method(FEM) was used to investigate the distribution of residual stress in several sapphire brazed joints. Models of the sapphire joints were built, pure Al and 2024 Al alloy were used as the fi ller metals, and residual stress in these conditions were simulated. Moreover, the condition with 2024 alloy as fi ller metal and an additional heat treatment were investigated. The simulation indicated that the residual stress was minimum when pure Al was used as fi ller metal, while it was signifi cant when 2024 alloy was filler metal. Heat treatment could decrease the residual stress by 50%-70%. In all conditions, maximum residual stress located at the edge of the brazing seam, but not the center.