The aluminum borate whisker reinforced magnesium matrix composites (Al18B4O33w/Mg) were fabricated by pressure infiltration technique and extrusion-vacuum infiltration technique respectively to study the effect of extrusion forming on their mechanical behaviors. The microstructure of the composites was observed by scanning electron microscopy. The compressive strength was investigated and compared with that of the matrix alloy AZ91D. The results show that the extrusion forming could cause fracture of the whisker, but reduce the holes in the composite during impregnation and improve the interfacial bonding between the whisker and the matrix alloy. Compared with that of the matrix as-cast alloy AZ91D, the compressive strength of Al18B4O33w/Mg by the pressure infiltration technique was increased by 22%, while that of Al18B4O33w/Mg by the extrusion-vacuum infiltration technique was increased by 120 %.
Short carbon fiber reinforced AZ91D alloy (Csf/AZ91D) was fabricated by the infiltration-extrusion method. The short carbon fiber preform was infiltrated with melted AZ91D alloy under the assistant of gas pressure. The extrusion processing was applied following the infiltration processing directly. The tensile property and microstructure of the Csf/AZ91D and that of the die-casting and extruded AZ91D alloy was compared. The results show that the short carbon fiber reinforced AZ91D alloy present excellent tensile property. The tensile strength and modulus of elasticity of Csf/AZ91D is about 50% and 18% higher than that of cast AZ91D alloy, respectively. The elongation to fracture of Csf/AZ91D is about 50% lower than that of AZ91D alloy.
Ouyang Haibo Li Hejun Qi Lehua Li Zhengjia Su Lizheng Wei Jianfeng
