Investigation On Preparation Of SiC_p/Al-13Si-Cu-Mg Composites And High Temperature Holding On Properties

Particulate reinforced aluminum matrix composites are proverbially used in automotive industry, aviation and aerospace, electron, war industry and physical culture due to their low density, high specific strength, high specific stiffness, low coefficient of thermal expansion, favorable thermostability, heat conduction, and wear-resisting property. Some important application results were obtained about particulate reinforced aluminum matrix composites recently, however the mechanical property of material can’t satisfy the use requirement of piston alloy, and the preparation process can’t meet large-scale industrial production.In order to achieve a new high-strength Al alloy with good performance of comprehensive to meet the material requirement of piston alloy, powder metallurgy with mechanical agitation method was used to prepare SiCp/Al composites in this paper. Minor enhancement particle addition to the aluminum and uneven distribution problem of SiCp were solved by high shear agitation. The interface structure was observed by means of SEM and TEM.In addition, in order to analyze the relationship between microstructure and mechanical property under high temperature and pressure conditions, the relational model of microstructure and macroscopic properties was builded. High temperature lasting test of piston alloy was conducted under 350℃ primarily. By means of OM、SEM and TEM observation, the effects of the high temperature lasting on microstructure and mechanical properties were investigated.Effect of fabricating parameters on the SiCp distribution state in SiCp/Al composites by powder metallurgy was investigated systematically. After effect of fabricating parameters on the SiCp distribution state in SiCp/Al composites by mechanical agitation method was investigated. The blending strength of SiC particles under the conditions of 700℃ and stirring for 5min was improved by high shear procedure. By means of SEM, TEM and HRTEM observation, the results showed that:the interface types of SiCp/Al include amorphous layer interface and clean interface, and the amorphous layer interface account for the majority. The formation of amorphous layer interface was associated with the interface of the magnesium concentration and the accumulation of impurity phase.High temperature lasting test of piston alloy showed that, the lasting time of increased with the applied load decreasing. When the applied load was decreased to 30MPa, the lasting time added to 102h.TEM shows that the change of mechanical property was caused by the θ"-θ’-θ progress of rich-Cu phase and dissolution of θ".