微切削加工中材料微观结构效应的有限元分析

Finite Element Analysis of Material Microstructure Effect in Micro-cutting Processes

为了研究材料微观组织结构对微切削加工中尺寸效应的影响,建立了一种基于材料微结构特征的正交切削有限元模型,工件采用非均质材料模型。仿真结果表明:当材料微观组织结构一定时,不同的加工尺度下产生不同的切屑形态;当切削厚度从上百微米下降到几个微米时,切屑由连续状向准静态挤压状转换,切削厚度越接近最小金相颗粒的尺寸,挤压状切屑越明显;在应力分布图上可看出,加工中最大的应力不仅出现在刀刃周围,还出现在异相颗粒之间的晶界处,说明多相材料在微尺度加工下微观结构效应显著。

In order to investigate the influences of material microstructure on the size effect in micro cutting,a microstructure-level simulation model was developed to characterize machining behavior of heterogeneous materials.The results show that,for a given material microstructure,the chip morphology changes as the uncut chip thickness changes.When the uncut chip thickness is decreased from hundred microns to few microns,the chip formation changes from continuous to a quasi-shear-extrusion,and the uncut chip thickness is more close to the size of the smallest grain,the extrusion is more obviously;in the stress diagram,the maximum stress appears around the tool edge and the grain boundary.It illustrates that the material microstructure effect is prominence during micro cutting processes.