K24镍基合金钎焊接头热应力的有限元模拟

Finite element simulation of thermal stress on brazed K24 nickel-based joint

采用有限元方法,模拟计算了镍基合金粉末钎料在1270℃钎焊K24镍基合金时,接头在冷却过程中的热应力最大值和应力集中区.结果表明,在冷却过程中,K24合金接头的切应力主要集中在界面端点处,且切应力的最大值出现在镍基钎料/K24合金界面的右端点处,其随着温度的降低先减小后增大.同时,接头x方向拉应力最大值也出现在此处,且其随着温度的降低经历由负到正的变化过程.当承受外切切力时,接头并非在镍基钎料内部断裂,而镍基钎料/K24合金界面易成为接头的主要断裂区.

By means of finite element method,maximum value of thermal stress and stress concentration zones of K24 nickel-based alloy joint brazed at 1 270 ℃ were simulated in this paper.The results show:during cooling process,the shear stress of K24 alloy joint concentrates at the interface tip and the maximum value of the shear stress appears at the right tip of Ni-based brazing alloy/K24 alloy interface,which decreases and then increases during cooling process.At the same time,the maximum value of stress in x direction of K24 alloy joint also appears on this site,which changes from negative to positive during cooling.After the temperature declines to room temperature,the joint seldom fractures in brazing alloy.Ni-based brazing alloy/K24 alloy interface easily becomes fracture zone as external force acts on the joint.