关键词: 石墨切削, 边位印压, 裂纹产生, 裂纹扩展

Abstract:

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.

Key words: graphite cutting, edge- indentation, crack initiation, crack propagation