In-Situ Study Of Effects Of Heat Treatments And Loading Methods On Fracture Behaviors Of A Cast Al-Si Alloy

In order to study the effects of heat treatment and loading methods on the dynamical fracture behaviors of Al-Si cast alloys, in-situ scanning electron microscope tensile/compression tests were performed. The results showed that the microcracks in a cast Al-Si alloy mainly originated from eutectic silicon particles and intermetallic compound particles, and particles with larger aspect ratios had a greater tendency to crack. In the non-heat treated alloy, the cracks preferentially propagated along the Al/Si eutectic interface, while in the heat-treated alloy, the cracks propagated mainly along the slip band. The cracks are almost parallel to the loading axis during compression, while they are mainly perpendicular to the loading axis during the tension process. At the same time, it was found that particles of 0-50 degrees or 130-180 degrees (the angle between the long axis of the particles and the loading axis) are more likely to break, independent of the heat treatments and loading methods.