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陶瓷-金属钎焊接头残余应力的数值分析

Numerical analysis of residual stress in ceramics/metal brazed joints

  • 摘要: 采用热弹塑性有限元方法,在考虑了材料性能参数随温度变化和界面反应层的情况下,计算了陶瓷/金属钎焊接头残余应力的大小和分布。通过计算发现:陶瓷/金属接头在冷却过程中产生的径向应力和剪应力对接头的影响较小,而在陶瓷表面的边缘接近焊缝的位置产生了最大的轴向拉应力,它影响接头的载荷承受能力,并且由于40Cr的屈服强度比45钢的高,计算出的Si3N4/40Cr接头的应力峰值比Si3N4/45钢的高。陶瓷/钎料和陶瓷/金属的界面反应层虽然薄,但它也是影响陶瓷/金属接头残余应力大小和分布的一个重要因素。另外,选择合适的钎料层、中间层和钎焊压力都可以有效地减小残余应力的峰值。

     

    Abstract: The residual stress in ceramics/metal joints was calculated by thermal-elastic-plastic finite element method in this paper.The influence of temperature on the material properties and the interface reaction layer was taken into account.The radial stress and shearing stress had a little influence on the joints,but a peak axial tensile stress which influenced on load-bearing capacity of joints occurred at the ceramic surfaceson the edges.The maximum of residual stress of Si3N4/40Cr brazed joints is higher than that of Si3N4/45 steel joints,because yield strength of 40 Crsteel is higher than that of 45 steel.Though the reaction layers of inter-faces are thin,they are important factors which influence on residual stress.In addition,the peak residual stress can be reduced by appropriate filler metal,interlayer and brazing pressure.

     

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