Tensile properties and fracture mechanisms of ZnO and ZnAl2O4-coated Al18B4O33 whisker reinforced aluminum composites

ZnO and ZnAl2O4-coated Al18B4O33 whisker reinforced pure aluminum composites were fabricated by squeeze casting. The effects of the coating contents on the ultimate tensile strength (UTS), 0.2% proof stress (σ0.2) and elongation to fracture (δ) of the composites were investigated. The results show that the UTS of ZnO-coated Al18B4O33 whisker reinforced aluminum composites increases almost linearly as the coating contents increase. However, the UTS of ZnAl2O4-coated Al18B4O33 whisker reinforced aluminum composites declines initially and increases later. The ZnAl2O4 coating of the whiskers is more favorable for an increase in the σ0.2 of the composites. The δ of the composites obtains its maximum value with an appropriate coating content. Fracture mechanisms of the composites were also investigated.