Study On Microstructure And Properties Of Mg₂Si/AM60 Magnesium Matrix Composites Prepared By In-situ Reaction

Magnesium alloy has a great potential to be applied in automobile and aerospace industries because of their light weight, high specific strength, excellent Good cast-on outwell ability and good machine ability as compared to other structural metals. So, magnesium alloy is one of the focuses at present. But its strength and high temperature creep resistance are worse, But magnesium matrix composite is able to improve these function deficiency.Intermetallic compound Mg₂Si is an ideal reinforcing phase in metal matrix composites. Making using of the characteristics of Am60 alloy, Mg₂Si phase can be formed in the process of solidification. However, Mg₂Si often exists in the shape of coarse Chinese script in the matrix, which greatly damages the strengthening effect of Mg₂Si. On the base of the analysis of the formation process of Mg₂Si phase, the effects of Si and Al content on the microstructure of Mg₂Si/AM60 composites were systemically studied, and the modifying effect of Sb, Y on Mg₂Si phase in the composites was also studied. Finally, high temperature creep resistance of the prepared Mg₂Si/AM60 composites was investigated.The results show that with the increase of Si content in Am60 alloy, the amount of Mg₂Si in the solidified samples increases, and its shape becomes more full Chinese script. The addition of Si in the AM60 alloys the shape of coarse Chinese script is found with the addition of Si.After adding Sb and Y, the phases of AM60 and Mg₂Si phase have been refined. Mg₃Sb₂ phase andAl₂Y phase act as heterogeneous core,the shape of Mg₂Si could be transformed from the Chinese script into uniformly dispersed particles. Therefore, Mg₂Si/AM60 composites with more desirable microstructure can be obtained, as a result, the mechanical properties of the composites can be further improved and high temperature creep resistance of the composites is better than AM60 alloy.