Abstract: Using Al63-Cu22-Ti5-Si10 as brazing alloy, vacuum brazing between 55% vol. SiC particle reinforced aluminium matrix composites (55% SiCp/Al MMCs) and kovar alloy was investigated. The effects of brazing temperature and different plating material on the surface of SiCp/Al MMCs on joint shear strength and joint microhardness was analyzed, respectively. The microstructure characteristic of joint was studied as well. The results indicate that brazing temperature and plating material have significant influence on the joint mechanical property. With the same brazing processing parameters, the shear strength of specimen SiCp/Al MMCs covered by copper is much higher than those of covered by nickel and non-cover. The maximum shear strength can reach 92. 8 MPa. With the increasing of brazing temperature from 560 ℃ to 580 ℃, the shear strength decreases gradually and then increases. For the specimens with different plating material, the maximum shear strength of joint can be achieved at the brazing temperature 560 ℃. With the same brazing temperature, specimen covered by copper has the maximum microhardness and the specimen covered by nickel has the minimum microhardness. The microstructure of joint is quite dense and free from defects such as void and non-wetting area. After brazing, the plating metal has disappeared and it was replaced by brazing alloy. By using brazing filler alloy Al63-Cu22-Ti5-Si10 , the reasonable brazing temperature is 560 ℃ and the reasonable plating material is copper on the surface of composite under the parameters of vacuum degree 6 . 5 × 10 -3 Pa and soaking time 30 min.

Key words: aluminium matrix composite;vacuum brazing;temperature;plating material