In situ TiB2 particulate reinforced near eutectic Al–Si alloy composites

Abstract

In situ TiB2 particulate reinforced near eutectic Al–Si alloy composites fabricated by the melt reaction composing (MRC) methods have been investigated. It has been shown that minute TiB2 particles (less than 1 μm) uniformly distribute in the eutectic structure and they are interlaced with the coralline-like eutectic Si, while there are very few TiB2 particles in α-Al. It has been also shown that in situ TiB2 particles can enhance the tensile strength of the Al–Si alloy matrix. The strengthening effect increases with increasing TiB2 content. The ultimate tensile strength (UTS) at room temperature of as-cast 6%TiB2/Al–Si–Mg composite is 296 MPa, that is a 14.7% increase over the matrix, and its elongation at fracture is 5.5%. After heat-treatment (T6), the UTS of the composites reaches 384 MPa. The strengthening mechanism has been discussed.