接头形式对陶瓷/金属连接残余应力的影响
Effect of joint types on residual stress in ceramic metal joint
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摘要: 采用有限元数值模拟方法研究了用AgCuTi钎料并添加Kovar中间层对氧化铝陶瓷/不锈钢进行钎焊连接接头残余应力的分布情况,分析接头形式对残余应力的影响。结果表明,采用等壁厚直接对接接头时,接头最大等效应力高达600 MPa以上,而将不锈钢壁厚减半后再进行对接时,接头最大等效应力可以降低近200 MPa;两种情况下最大等效应力均出现在靠近连接界面的陶瓷中,断裂易在此位置发生。考查了各应力分量对最终残余应力的贡献,结果显示轴向应力和剪切应力在靠近界面的陶瓷侧有较大残余拉应力是造成接头强度降低的主要因素。Abstract: By means of finite element numerical simulation, the effect of joint type on residual stress in ceramic/AgCuTi/Kovar/steel joint was investigated.The results show that in the direct butt joint the maximum residual stress is higher than 600 MPa.And halved the thickness of the steel cylinder, the residual stress of the joint can be reduced by 200 MPa compared with that in the direct butt joint.At both cases, the maximum residual stress value occurs on alumina ceramic near the brazing alloy/alumina ceramic interface. The fracture also occurs at this position.The radial stress and circumferential stress have little influence on the joints.And the axial stress and shear stress which have the peak tensile stress in alumina ceramic are the main factors which decrease the properties of the ceramic/metal joint.