Genetic Characteristics And Mechanical Properties Of High-silicon Aluminum Alloy Prepared By Rapid Solidification And Spark Plasma Sintering

High silicon aluminum alloy has small density, high strength, good abrasion resistance, good casting, processing and excellent performance, good dimensional stability,and many other advantages, is widely used in aerospace, automotive, machinery and other industries. Aluminum silicon alloy can show good control performance, improve the hyper-eutectic silicon content to improve the materials performance is very good, but the increase of silicon content generally makes the particle phase is thick patches, primary silicon the group features lower alloy material mechanics performance and machining performance. Using different technology can refine and change the size and morphology of crystal and eutectic silicon in the early phase, for example, modification, alloying,semi-solid forming and rapid solidification technology. At present, adopting traditional inoculation and alloying process are not completely solve the problem of primary coarsening, and the use of rapid solidification cooling rate(102~106 ℃/s) preparation of eutectic aluminum silicon alloy, can significantly improve the high silicon alloy microstructure, reduce the composition segregation and improve alloy solid solubility,improves the performance of the alloy increased significantly, with distinct from conventional casting alloy organization performance characteristics.Discharge plasma sintering(SPS) is a new type of powder material sintering molding method, obtained the rapid development in recent years. SPS using pulse energy, pulse discharge pressure and joule heat generated high frequency, instantaneous high temperature sintering process to complete, has the heating and cooling speed, the advantages of low sintering temperature and sintering time is short, can effectively inhibit the grain growth,maintain rapid solidification microstructure, compared with the traditional method has obvious advantages.In this paper, a ultra-fine grain Al-25 Si bulk materials were prepared by melt spinning rapid solidification combined with ball-milling and spark plasma sintering(SPS). It is found that, the rapid solidification microstructure and properties of alloy can be preferably reserved. The primary Si phase were uniformly dispersed in matrix with the sintering temperature of 320 ℃ and pressure of 500 MPa. The grain is very fine. Si element is supersaturated in the matrix, the density of alloy is above 98 %. The micro-hardness and the yield strength are 198 Hv and 682.2 MPa, respectively. Therefore, the prepared alloy possesses excellent mechanical properties.