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激光加工−预氧化Ma956合金与3YSZ陶瓷空气反应钎焊接头力学性能

Mechanical properties of laser-processed pre-oxidized Ma956 alloy and 3YSZ ceramic joints via reactive air brazing

  • 摘要: 为提高Ma956合金与3YSZ陶瓷的钎焊接头力学性能,采用激光加工和预氧化复合处理,在Ma956合金表面制备了周期性的Al2O3层覆盖沟槽结构,以抑制基体元素氧化并改善接头性能,通过空气反应钎焊方法将处理后的Ma956合金与3YSZ陶瓷连接. 结果表明,随着激光加工次数的增加,接头抗剪强度先升高后趋于平稳. 当激光加工100次,沟槽深度达到约39.9 μm时,接头强度达到最大值73.1 MPa,且断裂模式由脆性断裂转变为韧性断裂;有限元分析结果表明,合金侧的反应层是接头应力最集中的区域,激光加工沟槽可以使反应层的正应力由拉应力转变为压应力,同时降低切应力,从而有效抑制钎料拔出和裂纹扩展,显著提高接头的抗剪强度.

     

    Abstract: In order to improve the mechanical properties of brazed joints between Ma956 alloy and 3YSZ ceramics, a composite treatment of laser processing and pre-oxidation was adopted to prepare a periodic groove structure covered with an Al2O3 layer on the surface of Ma956 alloy, so as to inhibit the oxidation of matrix elements and improve the performance of joints. The treated Ma956 alloy was joined to 3YSZ ceramics via reactive air brazing. The results show that with the increase in the number of laser processing passes, the shear strength of the joint first increases and then tends to stabilize. When the laser processing is performed 100 times, and the groove depth reaches about 39.9 μm, the joint strength attains a maximum value of 73.1 MPa, and the fracture mode transforms from brittle fracture to ductile fracture. Finite element analysis results show that the reaction layer on the alloy side is the most stress-concentrated region of the joint. The laser-processed grooves can convert the normal stress of the reaction layer from tensile stress to compressive stress, while reducing the shear stress, thereby effectively inhibiting the pullout of brazing filler metal and crack propagation and significantly improving the shear strength of the joint.

     

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