The microstructure and mechanical properties of Mg2B2O5 whisker-reinforced ZK60 composites fabricated by powder metallurgy

ZK60 magnesium matrix composites were prepared by a powder metallurgy method which including ball milling, hot pressing sintering and hot extrusion and reinforced with varied mass fractions of Mg2B2O5 whiskers (3%, 5%, 7%, 9%, and 15%). The effects of the precipitated phase, reinforcement and texture on the mechanical properties of the as-extruded Mg2B2O5w/ZK60 magnesium matrix composites were investigated. The results show that the 7 wt% Mg2B2O5 whiskers were uniformly distributed in the matrix, and the average grain size of α-Mg in the composites was finer than that in the as-extruded ZK60 alloy. The transmission electron microscopy images show no obvious defect although the interfacial bonding between the Mg2B2O5 whisker and the matrix was mechanical bonding. Versus the as-extruded ZK60 alloy, the texture is enhanced by the addition of Mg2B2O5 whisker into the magnesium matrix. In addition, the tensile yield strength (TYS) and the compression yield strength (CYS) of the 7 wt% Mg2B2O5 whisker-reinforced ZK60 composites increased by 14.1% and 40.3%, respectively. Hall-Petch strengthening and load transfer are the main mechanisms for 7 wt% Mg2B2O5 whisker-reinforced ZK60 composites in the composites.