中间层对高体积分数SiC_p/Al复合材料真空钎焊的影响

Effect of filler metal on vacuum brazing of high volume fraction SiC_p/Al composites

采用铜箔、Al-Si-Mg及Al-Si-Mg/Cu/Al-Si-Mg(简称ACA)3种不同中间层对高体积分数45%SiCp/Al复合材料进行真空钎焊连接研究.通过SEM,EDS及XRD等方法对钎缝的微观结构及界面组织进行了分析,研究了中间层种类对钎焊接头微观结构、界面组织以及连接强度的影响,阐明了不同中间层钎焊连接45%SiCp/Al复合材料的界面形成过程及接头断裂机制.结果表明,ACA中间层兼具了铜和Al-Si-Mg钎料的优点,可降低钎料的液相线,增加其流动性,通过Cu原子优先在铝合金基体与其氧化膜的界面处扩散发生共晶反应,增强钎料的去膜作用,从而实现高体积分数45%SiCp/Al复合材料的高质量连接.

Three different filler metals,Cu foil,Al-Si-Mg foil and Al-Si-Mg / Cu / Al-Si-Mg( ACA) composite foil,were used for vacuum brazing of 45% SiCp/2024 Al composites. The microstructure of the interface in brazed seams was examined with SEM,EDS and XRD. And the effect of different filler metals on the interfacial microstructure and bonding strength was also analyzed. The formation of interface during vacuum brazing of 45% SiCp/2024 Al composites with different filler metals and the fracture mechanism of the joint were revealed. The results indicate that ACA composite filler metal,combining the advantages of both Cu foil and AlSiMg foil,had lower liquidus temperature and better flowability. Through the diffusion of Cu atoms and prior eutectic reaction at the interface between aluminum alloy substrate and its oxide film,the removal ability of oxide film of the filler metal was enhanced and joining of 45% SiCp/ Al composites was achieved with high quality.