蓝宝石/4J33合金钎焊接头残余应力的数值模拟分析

FEM analysis of distribution of thermal stresses at sapphire/kovar alloy brazed joint

采用有限元法和弹塑性理论,结合ANSYS15.0软件,对使用Ag-Cu-Ti8为钎料的蓝宝石/4J33合金活性钎焊接头的温度场和应力场进行了数值仿真模拟.温度场分析得到钎焊接头不同位置降温的快慢情况,应力场分析得到蓝宝石内最大拉应力位于外侧端面,为538 MPa,并向界面延伸,通过实际拉伸试验得出接头断裂部位与模拟结果吻合,当钎料层厚度为150μm时,径向残余应力最小,因而可以选择适当的钎缝层厚度以减少残余应力,文中的模拟计算结果能有效指导蓝宝石/4J33合金活性钎焊工艺,有利于保证实际接头强度和可靠性.

Using ANSYS finite element software,the stress field and temperature field of brazed joint which brazing filler metal is Ag-Cu-Ti8 was simulated between Sapphire and kovar alloy by the means of elastic-plastic analysis.It is simulated that the different positions temperature has changed and filler metal thickness has effect on residual stress and its distribution.It is concluded that the best radial tensile stress of sapphire is 538 MPa in peripheral surface and extends to the border.The calculation results suggested that the real fracture pattern was consistent with the analysis of the finite element method.When the filler metal thickness is 150 μm,this would be lowest stress.Brazing parameters were optimized so that the reality brazing process can be operated.