Effects of Ti-coating layer on the distribution of SiCp in the SiCp/2014Al composites

A Ti5Si3 coating layer was plated on the surface of SiCp by salt-bath plating. The coating layer greatly promoted the wettability of SiC by the molten Al with the final contact angle decreasing from 94 of uncoated one to 4 at 973 K. The 2 vol.% Ti-coated SiCp/2014A1 composites were fabricated by stir casting with the addition of 20 vol.% Ti-coated SiCp/2014A1 master alloy. Due to the significant improvement of the wetting between the Ti-coated SiC and Al melt, the interfacial energy between Ti-coated SiCp and Al melt is significantly higher than that between ot-Al and Ti-coated SiCp. Therefore, Ti-coated SiCp was more easily engulfed into ot-Al grains during solidification, leading to a more homogeneous distribution of SiCp and obvious improvement of tensile property for the composites. The yield strength, ultimate tensile strength and fracture strain of the 2 vol.% Ti-coated SiCp/2014Al composites increased from 389 MPa, 525 MPa and 4.8% of the 2 vol.% uncoated SiCp/2014Al composites to 420 MPa, 576 MPa and 6.8%, respectively. The present work offers a new method to improve the dispersal uniformity of SiCp in the composites. (C) 2015 Elsevier Ltd. All rights reserved.