Investigation on the Microstructure and Friction Wear Behavior of In-Situ TiC-TiB2/Al-12Si Composites Fabricated by Ultrasonic Assisted Laser Deposition

In-situ TiC-TiB2/Al-12Si composites were fabricated by ultrasonic assisted laser deposition using Ti, B4C and Al-12Si powders as precursor materials with different proportions. The phase constitution, microstructure, frictional wear behavior of the composites were analyzed by XRD, EDS, OM, SEM, friction and wear testing machine and 3D profile measurement. The results show that the alpha-Al phase is refined with the increase of Ti+B4C content, and the rod-like TiB2 synthesized in-situ can act as the heterogeneous nucleation core of alpha-Al phase. The TiC synthesized in-situ is a polygonal shape of 150 nm. The wear resistance of in-situ TiC-TiB2/Al-12Si composites is improved. The wear mechanism of Al-12Si alloy without Ti+B4C addition is fatigue wear, and the wear mechanism of TiC-TiB2/Al-12Si composites changes from fatigue wear to abrasive wear when the addition of Ti+B4C is 8wt%. When the addition of Ti+B4C is 10wt%, the wear mechanism of TiC-TiB2/Al-12Si composites is fatigue wear.