2004 Volume 22 Issue 4 Pages 542-550
Residual stress in an E-Sialon/SKS3 joint with a brazed metal larger of BAg8 was analyzed by using an elasto-plastic-creep FEM model. The joint was brazed at 1113K and cooled under different cooling conditions to room temperature. Before the analysis, creep deformation characteristics of SKS3 and BAg8 were examined by means of tensile test at high temperatures. It was found that creep deformation occurs in SKS3 at above 673K and BAg8 at above 473K. These creep data were adopted for the analysis of residual stress in the E-Sialon/SKS3 joint bonded under different cooling conditions. Based on the analysis, cooling process for reducing the residual stress in the joint was discussed. In a cooling rate of 10K/s – 0.001K/s, it was found that the residual stress after cooling decreases as the cooling rate decreases. This means that a stress relaxation occurs during cooling due to the creep deformation of SKS3 and BAg8, in which the creep deformation of BAg8 was estimated to be especially large. Moreover, effect of maintaining at a constant temperature in the cooling process was discussed for reducing the residual stress. It was found that the maintaining for 3600s at 523K is quite effective for reducing the residual stress in the joint cooled to room temperature.
