用三维电镜图像数据测试空穴形状

用碳化硅强化金属基复合材料制作的不同切口的拉伸试样进行了拉伸试验并使用三维电子扫描显微镜对拉伸延性断面进行了微小空穴的三维形状测试，分析了在不同应力三维度下空穴聚合时空穴几何形状的变化，为准确模拟金属基复合材料在多向外载荷下的损伤过程，判断延性损伤机理提供了科学依据。

MEASUREMENT OF VOID SHAPE FROM THE FRACTURE SURFACE USING THE 3-DIMENSIONAL SEM DATA

The tensile tests are conducted and the void shape is measured using the 3-dimensional SEM (scanning electron microscope) on the tensile test ductile fracture surface by changing the notch radius of tensile test specimens, which is made of the SiC reinforced metal matrix composite material. The effects of void configuration and coalescence under the different stress-triaxiality condition are analyzed. The results show that the average void aspect ratio increases with the average void size. It means that the stress triaxiality and strain constraint play an important role during the damage process. These experimental results could be used to correctly simulate the ductile damage process of the metal matrix material under the multi-dimensional loads, to propose a reasonable strength evaluation method and to reveal the ductile damage mechanism.