Effect of addition of 3 %Al2O3 on mechanical and microstructural properties in Al-16Si hypereutectic alloys with pouring temperature

Abstract

It is well know that the mechanical properties of hypereutectic Al-Si alloys are affected by the size, volume fraction and distribution of primary and eutectic Si particles. However, the pouring temperature of the alloy also acts as the vital role for simultaneous refine and modifying Si particles in hypereutectic Al-Si alloys by conventional means. The particles distribution of nano particles on the melt is different at different pouring temperature which affects the physical, mechanical and the microstructural behavior of Al-Si alloys. Various content of gamma Al2O3 nano particles were added in hypereutectic Al-16Si alloy melt and further dispersed through an ultrasonic cavitation based technique. The cast hypereutectic Al-16Si alloy with the nano particles’ addition showed a significant enhancement in hardness, strengths and ductility. The wear behaviour of the materials depends on the distribution of intermetallic compound over melt. This paper suggests that gamma Al203 nano particles effectively induced simultaneous refinement of primary Si and modification of eutectic Si, resulting in superior ductility enhancement that is much higher than those conventional methods can offer. Moreover, the large plate eutectic Si particles were also modified into fine core particles. The result could have great potential for numerous applications. The experiment has been performed on a group of specimens under different loads and with different speeds. We observe from the experiment that, with the increase in Al2O3 content wearing tendency decreases due to formation of Al-Si intermetallic compounds.