高体积分数铝基复合材料Zn基钎料钎焊接头组织与性能

为了拓展高体积分数（70%）SiC颗粒增强铝基复合材料在电子封装领域的应用，从冶金思路出发，通过添加降熔元素Mg和Ga以改善钎缝/母材界面致密润湿，用3种Zn基中温软钎料在相同工艺参数（钎焊温度480 ℃，压力0.5 MPa，保温30 min）下钎焊铝基复合材料，重点分析了Mg、Ga元素的添加对钎焊接头组织、力学性能及润湿性的影响。Zn可深度扩散入基体内，改善基体/钎料（M/M）界面润湿性。力学性能试验结果表明:采用Zn-25Al-10Ga-9Mg-1Ti钎料（熔化范围418~441 ℃）获得了平均剪切强度为16.6 MPa的钎焊接头，均高于其他两种材料；采用优化后的1 MPa压力时，Zn-25Al-10Ga-9Mg-1Ti钎料接头剪切强度可达30 MPa。断裂表面和断裂路径分析表明，P/M（颗粒/金属钎料）界面是薄弱环节，同时钎缝中生成的块状Mg2Si相（含少量Al，约6%）也对接头的力学性能不利。3种含Mg量不同的钎料钎焊结果表明，Zn基钎料中Mg含量对M/M界面影响无显著差异，但对P/M界面润湿性与钎缝析出相（Mg2Si）有显著影响，这为优化Mg含量与钎焊规范（调控基体溶解与消除钎缝脆性）指明了方向。

Microstructure and Property of Aluminium Matrix Composites Joint with High Volume Fraction Using Zn-based Brazing Filler Metal

In order to expand the application of SiC particle-reinforced aluminum matrix composites with the high volume fraction(70%) in the filed of electronic packaging, from the metallurgy aspect, through adding Mg and Ga as the melting point depressant to improve the compactness and wettability of brazing weld/base metal interface, three kinds of Zn-based medium-temperature solder were used to braze aluminum matrix composites under the same technological parameters of brazing temperature 480 ℃, pressure 0.5 MPa and heat preservation 30 min. The influence of Mg and Ga on the joint microstructure, mechanical strength and wettability were investigated. Zn can be deeply diffused into the matrix to improve wettability of the base metal/filler metal(M/M) interface. The results of the mechanical performance test results showed that the brazing joints with an average shear strength of 16.6 MPa were obtained with the Zn-25Al-10Ga-9Mg-1Ti brazing alloy(melting range: 418~441℃), which were higher than the other two materials. The shear strength of Zn-25Al-10Ga-9Mg-1Ti brazing joint can reach 30 MPa with the optimized pressure of 1 MPa. The fracture surface and path analysis showed that the particle/filler metal(P/M) interface was the weak link, and the massive Mg2Si phase, which containing about 6% Al, generated in brazing joint was also unfavorable to the mechanical properties of the joint. The brazing results of the three brazing alloys with different Mg content showed that there was no significant difference in the influence of Mg content in Zn-based brazing alloys on the M/M interface, but it had significant influence on the wettability of P/M interface and the precipitation phase Mg2Si of brazing joints, which showed the direction of optimizing Mg content and brazing specifications(regulating matrix dissolution and eliminating the brittleness of brazing joints).