Structure-property analysis of in-situ Al-MgAl2O4 metal matrix composites synthesized using ultrasonic cavitation

In-situ Al-MgAl2O4 metal matrix composite was successfully manufactured using SiO2 with the aid of ultrasonication. MgAl2O4 particles and their clusters were identified at grain boundaries and interdendritic regions within the grain envelopes. The composite showed 2-5 fold reduction of grain size with respect to the reference alloy cast at similar conditions. The composite showed 10% increase in yield stress and 15% increase in UTS while maintaining the ductility similar to reference alloy. CTE mismatch strengthening and grain boundary strengthening are suggested to be influencing mechanisms in the improvement of mechanical properties.