为揭示石墨切削材料的去除过程和已加工表面的形成机理， 研究了石墨边位印压时裂纹的产生和扩展规律． 结果表明: 当印压载荷增加到某一临界值时， 裂纹突然产生并迅速扩展; 初始裂纹朝试件内部扩展， 然后逐渐向印压表面扩展， 最后到达印压表面， 裂纹扩展路径呈圆弧形; 随着压头楔角和印压厚度的增加， 裂纹愈朝试件内部扩展， 在试件表面留下的凹坑深度和宽度愈大． 切削实验结果表明， 边位印压裂纹的产生和扩展规律能很好地解释石墨切削时切屑的去除过程和已加工表面的形成原因．

In order to reveal the cutting process of graphite materials and the forming mechanism of machined sur-faces,the crack initiation and propagation laws of a graphite specimen subjected to edge- indentation are investigated.The results show that (1) cracks initiate suddenly and propagate rapidly when the indentation loading increases to acritical value; (2) initial cracks spread toward the inside of specimens,and then propagate toward the indentationsurface gradually and reach the indentation surface finally,which occurs along an arc- shaped propagation path; and(3) as the interior angle of indenter and the edge- indentation thickness increase,the cracks spread farther towardthe inside of specimens and the depth and width of concavities forming on the specimen surface become greater.Inaddition,cutting experiments indicate that the crack initiation and propagation laws of the graphite specimen sub-jected to edge- indentation can be used to describe the material removal and the machined surface formation.