Al-20Cu-9.6Si-xEr钎料对SiC_p/A356复合材料真空钎焊接头组织与性能的影响

Effect of Al-20Cu-9.6Si-xEr Filler Metal on Microstructure and Properties of Brazed Joints for SiC_p/A356 Composites by Vacuum Brazing

采用不同铒含量的7组Al-20Cu-9.6Si-xEr钎料分别对SiCp/A356复合材料进行了真空钎焊。利用扫描电镜和能谱分析等方法对接头微观组织进行了观察和分析。通过剪切实验对钎焊接头的抗剪强度进行了测定,并对剪切断口的微观形貌进行了观察。结果表明：添加稀土后,钎焊接头的抗剪强度明显提高。当w（Er）=0%时,钎缝处SiC颗粒聚集严重,接头强度为43.5MPa;当w（Er）=0.05%时,钎缝边界无SiC颗粒的聚集,接头强度最高,达到68.6MPa;当w（Er）=0.1%-0.4%时,钎缝处SiC颗粒聚集趋势减弱,接头强度值在45.3-50.5MPa之间;当w（Er）=0.5%时,SiC颗粒分布在钎缝内部,接头强度明显提高,达到62.2MPa。

SiCp/A356 composites were brazed with seven kinds of Al-20Cu-9.6Si-xEr filler metals in vacuum.Microstructure of the brazed joints was observed and analyzed by SEM and EDS.Shear strength was evaluated by shear test,and microstructure of the fracture was observed.The results show that the shear strength of the brazed joints is significantly improved when Er is added.When the content of Er is 0%（mass fraction）the aggregation of SiC is very serious,and the shear strength is43.5MPa.There is no aggregation of SiC in brazing seam boundary,and shear strength reaches the maximum 68.6MPa when the content of Er is 0.05%.The aggregation of SiC is weakened and the shear strength is between 45.3-50.5MPa when the content of Er is between 0.1%-0.4%.The SiC particles are distributed inside the brazing seam,and the joint strength significantly increases to62.2MPa when the addition amount of Er is 0.5%.