The influence of pure Na on the microstructure and tensile properties of Al-Mg2Si metal matrix composite

In current research, the influence of different concentrations of Na (0.01–0.2 wt.%) on the microstructure and tensile properties of Al-15 wt.%Mg2Si in situ metal matrix composite has been investigated. It was found that 0.1 wt.% Na addition changes the morphology of primary Mg2Si irregular or dendritic to polyhedral shape and its average particle size decreases from 32 μm to 7 μm. Microstructural studies also showed that the morphology of the eutectic Mg2Si phase alters from flake-like to very short fibrous or dot-like. Further investigations on tensile tests revealed optimum Na level (0.1%) for improving both UTS and elongation values.

► Effect of Na contents on the microstructure of Al-15%Mg2Si composite.
► The optimum concentration of Na was found to be 0.1 wt.%.
► Ultimate tensile strength values changed from 240 MPa to 272 MPa by adding Na.
► The addition of 0.1 wt.% Na increased the elongation values from 2.6% to 4.5%.
► Na addition conducted the fracture behaviour of the composite from brittle to ductile.