中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 15 No. 5 October 2005 |
(School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China)
Abstract: Mixed Al-Si, Al-Si-SiC and Al-Si-W powders were employed as insert layers to reactive diffusion bond SiCp/6063 MMC. The results show that SiCp/6063 MMC joints bonded by the insert layer of the mixed Al-Si powder have a dense joining layer with a typical hypoeutectic microstructure. Using mixed Al-Si-SiC powder as insert layer, SiCp/6063 MMC can be reactive diffusion bonded by a composite joint. Because of the SiC segregations, however, there are a number of porous zones in the joining layer, which results in the low shear strength of the joints, even lower than that of joints reactive diffusion bonded by the insert layer of mixed Al-Si powder. The W added into the insert layer of Al-Si-W nearly all reacts with Al to form intermetallic WAl12 during bonding. The reaction between the W and Al facilitates to form a dense joint of high quality, and the formed intermetallic WAl12 has a reinforcing effect on the joints, which lead to the high shear strength of the joints. In general, under the condition of fixed bonding time (temperature), the shear strengths of the joints increase as the bonding temperature (time) increases, but tend to a maximum at bonding temperature of 600℃(time 90min).
Key words: reactive diffusion bonding; insert powder layer; SiCp/Al MMCs