纳米SiC增强AZ91D复合材料高温拉伸及断裂行为

采用复合分散铸造法制备了纳米SiC颗粒(n-SiCp)增强AZ91D复合材料,研究了复合材料在高温下的拉伸及断裂行为。结果表明:n-SiCp的加入可以提高复合材料的高温拉伸强度,高温下n-SiCp对复合材料的增强效果比室温更加明显;n-SiCp的加入还显著提高了复合材料在高温下的断后伸长率,复合材料具有较好的高温塑性。断口分析表明,n-SiCp的加入使复合材料在高温下的断裂行为由室温的脆性断裂为主转化为典型的韧性断裂。

Tensile Properties and Fracture Behavior of Nano-Sized SiC Particles Reinforced AZ91D Composites at Elevated Temperature

Magnesium (AZ91D) matrix nanocomposite reinforced with nano-sized SiC particles (n-SiCp) was prepared by mechanical stirring and high intensity ultrasonic dispersion assisted casting. The tensile properties and fracture behavior of the magnesium alloy and its nanocomposites at elevated temperature were investigated. The results show that the addition of n-SiCp to AZ91D can improve the tensile strength of the nanocomposites, especially at high temperature. Furthermore the significant improvement of the elongation of the nanocomposites at high temperature is achieved, which results in the quite good ductility at elevated temperature. The fracture analysis on the nanocomposites shows that the fracture mechanism of the nanocomposites changes gradually from the brittle fracture at room temperature to the typical tough fracture at high temperature due to the addition of n-SiCp.