EFFECT OF Cu ON THE MICROSTRUCTURE, HARDNESS AND TENSILE PROPERTY OF 15 wt.%Mg₂Si/Al-La COMPOSITES

The effect of different Cu contents (0 similar to 5%) on the microstructure and mechanical properties of 15wt.%Mg2Si/Al-La composite was investigated in the present work. The results show that Cu addition had a refining effect on the primary Mg2Si particles. The smallest particle size was acquired when 2% Cu was added. The UTS exhibited a parabolic tendency, which increased from 173 MPa to 227 MP by 31.21% and then decreased with further increasing Cu content. The UTS enhancement could be attributed to the appropriate content of Cu (2%) addition, which led to the formation of Cu-rich phases. When the Cu content was further increased, the UTS of the composite decreased for the coarsening of the Mg2Si particles and the increasing fraction of hard brittle phases.