AZ31-2％Si alloy was prepared by adding Si to the AZ31 melt.AZ31 and AZ31-2％Si alloy were processed by multi-cycle closed die compression at high temperature,and the microstructure and wear resistance were studied.The results show that the as-cast AZ31 alloy is composed of Mg and Mg17Al12,while the as-cast AZ31-2％Si alloy is composed of Mg,Mg17Al12 and Mg2Si.After five cycles compression at 400 ℃,grain of the AZ31 alloy is transformed from coarse equiaxed grain to fine recrystallized grain and Mg17Al12 phase is dissolved,and the vast majority of Mg17Al12 phase in the AZ31-2％Si alloy is dissolved into the matrix,the coarse Mg2Si phase is broken into fine particles and dispersed around grain boundaries.After sliding friction for 2500 m,the wear loss of the as-cast and five cycles compressed AZ31 alloy is 26.4 mg and 22.1 mg,respectively.The wear loss of the as-cast and five cycles compressed AZ31-2％Si alloy is 22.7 mg and 21.0 mg,respectively.The main factor for improving of wear resistance of the AZ31 alloy after compression is grain refinement.The main factors for improving of wear resistance of the AZ31-2％Si alloy after compression are grain refinement,Mg2Si phase refinement and its dispersive distribution.
Mg alloyclosed die compressionmicrostructureMg2Si phasewear resistance
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