Interfacial reactions and mechanical properties of 6061Al matrix composites reinforced with alumina-coated Al_18B_4O_33 whiskers

摘要

Sol-gelγ-Al_2O_3 and α-Al_2O_3 ceramic coatings were deposited onto surfaces of aluminum borate whiskers to control the spinel reactions between whiskers and matrix alloys. Interface observations, tensile experiments and hardness measurements of the composites were conducted to evaluate the coating effect. By comparison with γ -Al_2O_3 coating, the γ-Al_2O_3 coating was found to be more effective in controlling the interfacial reactions, and it helped to enhance the elastic modulus of the composite. The introduction of alumina coatings to the composite postponed the peak-aging process, due to a smaller depletion of magnesium in the matrix of the coated composites.