Structure control of in-situ silicon particle reinforced Zn [sbnd]27Al composite materials

Abstract

Al Si alloy is one of the most widely applied commercial alloys. Its properties can be improved by alloying with the element silicon, the morphology of the silicon phases having a direct effect on its properties. The modification of the needle-like eutectic silicon and plate primary silicon phase is importance for the mechanical properties of Al Si alloy. Zinc based aluminum alloy is also an important commercial alloy, one of its main applications being that of a wear-resistant material. It is composed of multiphases, but the microhardness differences of each phase is not great. If the number of dispersion hard phases (or particles) is well-distributed in the zinc based aluminum alloy, it is of no doubt that the abraiibility of the material is improved. The problem of how to prepare particle reinforced zinc based aluminum alloy composite is of concern to researchers. The purpose of this present study is to introduce a new process which can be used to prepare silicon particle reinforced zinc based aluminum alloy composite. The process is that the molten zinc based aluminum alloy mixes with rheologic (or semi-solid) hypercutectic Al Si alloy, the primary and eutectic silicon phases then acting as a particle reinforced phase in the zinc based aluminum alloy. The morphology of silicon phase can be controlled by stirring and modifying. The morphology of the silicon phase is regularly polyhedral, its size is about 10≈50 μm and it is well-distributed in the zinc based aluminum alloy. The results of wear-resistant test show that the silicon particle reinforced zinc based aluminum alloy composite is a good wear-resistant material.