Microstructure and mechanical properties of AlN particles in situ reinforced Mg matrix composites

AlN particles reinforced Mg-9 wt% Al matrix composites were in situ synthesized by bubbling nitrogen gas method. Nano-sized AlN particles were uniformly distributed in the matrix, which resulted in grain refinement of a-Mg from 90 to 100 µm to 30-40 µm after solutionizing, and then Mg17Al12 phase was dispersed and decreased. Subsequently, significant improvements of tensile strength (~226 MPa) and elongation (~21%) were obtained in the as-cast AlN/ Mg-9Al composites. The interface characteristic and tensile fracture surface were also analyzed.