Abstract:TiB₂/Al-30Si composites were fabricated via in-situ melt reaction under high-energy ultrasonic field. The microstructure and wear properties of the composite were investigated by XRD, SEM and dry sliding testing. The results indicate that TiB₂ reinforcement particles are uniformly distributed in the aluminum matrix under high-energy ultrasonic field. The morphology of the TiB₂ particles is in circle-shape or quadrangle-shape, and the size of the particles is 0.1-1.5 μm. The primary silicon particles are in quadrangle-shape and the average size of them is about 10 μm. Hardness values of the Al-30Si matrix alloy and the TiB₂/Al-30Si composites considerably increase as the high energy ultrasonic power increases. In particular, the maximum hardness value of the in-situ composites is about 1.3 times as high as that of the matrix alloy when the ultrasonic power is 1.2 kW, reaching 412 MPa. Meanwhile, the wear resistance of the in-situ TiB₂/Al-30Si composites prepared under high-energy ultrasonic field is obviously improved and is insensitive to the applied loads of the dry sliding testing.

Key words: TiB₂/Al-30Si composite; in-situ melt reaction; high-energy ultrasonic field; wear properties