高应变率下SiCp/Al的断口形貌和变形机制

Fracture morphology and deformation mechanism of SiCp/Al with high strain rates

利用Hopkinson压杆对采用无压浸渗法制备的高体积分数SiCp/Al复合材料进行高应变率冲击压缩实验,研究了应变率对复合材料微观断口形貌的影响,分析了其在高应变率下的变形机制.结果表明:强度较高的复合材料有较强的产生变形局部化的倾向;同时,SiC颗粒尺寸对局部化的形成有明显影响,增强相颗粒尺寸较小(100μm)的复合材料更容易产生变形局部化,在高应变率压缩载荷下,无压浸渗高体积分数SiCp/Al复合材料在增强相颗粒破裂的同时会出现基体的局部化变形,复合材料的损伤行为与材料中的增强相颗粒尺寸密切相关.

The impact experiment for SiCp/Al composites were conducted using the Hopkinson pressure bar at high strain rates.Effects of strain rate on the fracture morphology and impact deformation behavior of SiCp/Al composites were analyzed.The results show that the onset of deformation localization in SiCp/Al composites strongly depends on the particles size and the composites reinforced by smaller particles（100 μm） have high localized deformation under the same conditions.At loading with high strain rates,the damage mechanism of the high volume fraction particle reinforced SiCp/Al composite associated with the fracture of the particles and the deformation localization of the matrix.The damage mechanism of SiCp/Al composite is considerably sensitive to the particles size.