Study On Mg₂Si/AM60 Magnesium Matrix Composites By In-Situ Reaction Under Itensity Ultrasonic

Magnesium is a light structure metal. Magnesium's weigh is just for aluminum's 1/5 and zinc's 1/4 when they have the equal volume. Magnesium matrix composite is a competitive light metal matrix composite after the aluminum matrix composite. Its main characteristics are low density, high specific strength, specific stiffness and also has good abrasion resistance, high temperature resistant, excellent resistance to impact, excellent damping performance and good dimensional stability and casting property, etc. In order to overcome the limitations of single material performance, give full play to the characteristics of various materials, more and more people according to components'function requirement and working situation, choose two or more of different materials that have different chemical, physical properties and combine into a composite material with a certain way, scale and distribution. Through this method people can give full play to each component material, and satisfy the excellent characteristics of various special and comprehensive performance requirements. Since the 1980s to now, Magnesium matrix composite has become into Research focus, especially discrete magnesium matrix composite.Magnesium matrix composite reinforced by Mg2Si particles have been synthesized by direct melt reaction method under high intensity ultrasonic from AM60-Si system. The phase compositions and microstructures are been investigated with the help of OM, SEM, EDS and XRD. The analysis result show that under high intensity ultrasound,enhanced phase Mg2Si situ generated are more small and the agglomeration are been improved, acoustic cavitation generated transient high temperature, high pressure and acoustic streaming effects can reduce response time and improve the resultant in situ agglomeration when Melt under the high-energy ultrasound. Meanwhile, the introduction of the thermodynamic formula and Factors that affect the Mg2Si generated can prove high-energy ultrasound can promote the in situ reaction.On the basis of in-situ reaction, the effects of different ultrasonic power and time on microstructure and properties of composite materials of Mg2Si/AM60 magnesium matrix composites and the optimum power and reaction time can been defined. The Reinforcing phase particles Mg2Si has been refined with the ultrasonic power, and the distribution has also been significantly improved. Mechanical properties of composites increased with the ultrasonic power increased. When the ultrasonic power is 600W, Composite materials tensile strength than those not exert ultrasonic in-situ composite improved 11.2%. Mg2Si reinforced particles were changed from Chinese script type and block type to granular type and fragmentation dendritic type, and peripheral obtuse, no sharp edges.