Microstructure and Mechanical Properties of an AlN/Mg-Al Composite Synthesized by Al-AlN Master Alloy

In this work, a kind of AlN particles reinforced Mg-Al matrix composite was fabricated by introducing Al-12.5AlN master alloy into the Mg melt during casting. In the 0.8AlN/Mg-8Al composite, the nano-sized AlN particles are uniformly distributed, exhibiting a clean interface with the matrix. The introduction of AlN results in the refinement of -Mg grains through modifying its dendrite morphology, and the -Mg17Al12 intermetallic was also changed from continuous coarse-like to fine morphology. As a result, compared with Mg-8Al matrix alloy, the tensile strength and elongation of the 0.8AlN/Mg-8Al composite were increased by 31% and 213%, respectively. The strengthening mechanism and fracture behaviors were discussed.