Alloy elements addition is thought as a important method to modify the Chinese script shaped Mg2Si phases in the microstructure of Mg-Al-Si based magnesium alloys,at present,the research and development about this method have received much attention all over the world,and consequently many researches have been carried out.

The research results indicate that after being solutionized,the Chinese script shaped Mg2Si phases in the microstructure of the alloy are modified,namely,their mo.

7Si alloy is composed ofα-Mg,M17Al12 and Mg2Si phases,and the Mg2Si phases appear obvious Chinese script morphology and very coarse.

In 6009 alloys,spherical Mg_2Si is the dominant strengthing phase.

The Mg_2Si particle reinforced hypereutectic Al-Si alloy in-situ composites are manufactured by liquid pouring.

Research progress of intermetallic compound Mg_2Si is reviewed with focusing on its properties,fundamental researches and applications.

The results indicated that the particles of α-Al phase,which were non-existent for non-stirring casting of Al-20%Mg2Si hypereutectic alloy,appeared for electromagnetic agitation and the primary Mg2Si with cluster distributed on the matrix of alloy.

The experimental results show that the Al-P or Al-Ti-B can refine and modify primary Mg2Si, and the refinement and modification efficiency of Al-P master alloy can be improved after the addition of Al-Ti-B.

So the Mg2Si particles reinforced aluminum matrix composites were in situ fabricated with 20wt% weight fraction.