高速切削锯齿形切屑表征的研究现状综述

Summary of Research Situation for Characterization of Serrated Chip Formed in High Speed Machining

研究高速切削形成的锯齿形切屑的表征有利于科学地阐释锯齿形切屑的形成机理。这种表征包括几何表征和物理表征。几何表征是从切屑的几何形状和形成机理上进行表征,几何形状可用切屑的锯齿化程度来表征,形成机理可分别用绝热剪切理论和周期性断裂理论来表征。物理表征包括锯齿形切屑的变形、显微硬度、微观组织结构的表征。切屑变形包括切屑单元变形和绝热剪切带变形,且后者大于前者;锯齿形切屑的显微硬度由绝热剪切带中心向外逐渐降低,且高于基体材料硬度;切屑内部的微观组织结构与基体材料的差异主要表现在绝热剪切带上,而绝热剪切带分为形变带和转变带,形变带表现为晶粒的细化和拉长,转变带则伴随着相变的发生。

The characterization of serrated chip formed in high speed machining is conducive to correct understanding of the serrated chip＇s formation mechanism.The characterization includes geometrical and physical ones.The geometrical characterization is analyzed based on the chip＇s geometric shape and formation mechanism.The segment degree is used to characterize serrated chip.The chip formation characterization can be theoretically divided into adiabatic shear theory and periodic brittle theory.The physical characterization,including chip deformation,micro-hardness and microstructure are reviewed.The chip deformation includes segment deformation and adiabatic shear band deformation,the latter is inhomogeneous and greater than the former.Micro-hardness of serrated chip gradually decreases from the center of adiabatic shear band to outward.The difference of microstructure between the chip and the bulk material is mainly on the adiabatic shear band.The adiabatic shear band is divided into deformation band which is mainly on the grain refinement and elongated as well as transformation band which is that the phase of material transformation.