切削过程中金属层流过剪切区发生塑性变形后形成切屑。抛光的板状纯铁作被加工材料,通过刨屑快速退刀获得的切屑,用光学显微镜及扫描电子显微镜观察切屑层片内的表面滑移带。滑移带的数量、形状和分布,可反映金属塑性变形的程度和方向,并可间接地推测位错均行为。滑移带间距为1—3μm,带与带之间基本上无塑性变形。层片宽度为30—50μm,比滑移带间距大一个数量级,各层片内有数量不等的滑移带。研究结果说明在一般切削条件下,(a_p=0.3,O.7mm),切屑形成由层片间发生相互变形和层片内晶面发生滑移引起的。 During the cutting process, the metal layer flows through the shear zone to form the chip after plastic deformation. Polished plate-like pure iron was used as the material to be processed, and chips obtained by rapid retraction of the shavings were observed. The surface slip bands in the chip layers were observed with an optical microscope and a scanning electron microscope. The number, shape and distribution of slip bands can reflect the degree and direction of metal plastic deformation and can indirectly infer the behavior of dislocation. Sliding belt spacing of 1-3μm, with no substantial plastic deformation between the band. The lamella width is 30-50μm, one order of magnitude larger than the slip band spacing, with a varying number of slip bands in each layer. The results show that under normal cutting conditions (a_p = 0.3, O. 7mm), the chip formation is caused by the mutual deformation between the layers and the slip of the crystal planes in the layers.