采用Ag47-Cu18-In17-Sn17-Ti1钎料, 分别在560, 570, 580 ℃下保温30 min对增强相体积分数为15%的SiCp/A356复合材料进行真空钎焊, 研究了钎焊接头的显微组织、显微硬度及抗剪强度, 并确定了最优的钎焊温度。结果表明: 在560~580 ℃温度区间进行真空钎焊获得的接头焊缝组织致密, 钎料对基体铝合金和SiC颗粒都具有良好的润湿性, 钎料中各元素在580 ℃下的扩散距离远大于在560 ℃下的; 随着钎焊温度升高, 焊缝中心及扩散区的显微硬度都逐渐下降; 最佳的钎焊温度为560 ℃, 在此温度下制备钎焊接头的抗剪强度可达51.8 MPa, 焊缝中心与扩散区的显微硬度分别为99.4 HV和110.7 HV, 接头的断裂方式表现为塑性断裂。

Taking Ag47-Cu18-In17-Sn17-Ti1 as brazing filler metal, SiCp/A356 composites containing 15vol% SiCp were welded by using vacuum brazing technology under the parameters of temperature 560 ℃, 570 ℃, 580 ℃ and soaking for 30 minutes. Microstructure, microhardness and shear strength of the joints were investigated, and then optimal brazing temperature was confirmed. The result indicate that in the brazing temperature range of 560-580 ℃, the compact brazed seam obtained. The brazing filler metal could wet both of the matrix aluminum alloy and SiC particles very well. The diffusion distance of elements in brazing filler metal at 580 ℃ was much longer than that at 560 ℃. The microhardness in brazed seam centre area and diffusion area gradually decreased with the increase of brazing temperature. The optimal brazing temperature was 560 ℃. At this temperature, the maximum shear strength of the jonts could reach 51.8 MPa, and the microhardness in brazed seam centre area and diffusion area was 99.4 HV and 110.7 HV, respectively. The fracture mechanism of the joint was characterized by ductile fracture.