Achieving high strength and high ductility in submicron-MgO/AZ31 composites with an innovative honeycomb-like structure

Honeycomb-like AZ31 matrix composites with 1, 2, and 4 wt% submicron-MgO were prepared using low-energy milling and extrusion. The composites consist of fine-grained and coarse-grained zones. The fine-grained zones enriched with submicron MgO form a honeycomb-like structure, and the coarse grains without MgO are filled into unit cells. Both the strengths and elongations of the newly developed MgO/AZ31 composites are enhanced compared with AZ31. Specifically, the tensile strength of composites containing 1 wt% MgO is improved to 344.1 MPa, and at the same time, its elongation is increased up to 21.5%. The excellent strength-ductility combination is due to the introduction of submicron-MgO reinforcements with unique distribution. Such achievements could be beneficial to the structural design of composites.