The strain gradient plasticity theory was used as the constitutive equation to illustrate the material properties at micro scale. The present paper employed the FEM to determine the distribution of effective stresses and strains when machining an AISI 1045 steel. The effect of the ratio of the uncut chip thickness to cutting edge radius on the distribution of effective stress and strain was analyzed.Orthogonal micro-cutting experiments were performed to obtain the chip roots to measure micro-hardness and metallographic sections of the chip roots. Strain gradient in the primary deformation zone
is proven to exist,which validates the simulation results.
Childs T,Maekawa K,Obikawa T,et al. Metal Ma- chining :Theory and Applications[ M]. Arnold : But- terworth-- Heinemann, 2000.
[3]
Elmadagli M, Alpas A T. Metallographic Analysis of the Deformation Microstructure of Copper Sub- jected to Orthogonal Cutting[J]. Materials Scienceand Engineering, 2003,355 : 249-259.
[4]
Woon K S, Rahman M, Fang F Z, et al. Investiga- tions of Tool Edge Radius Effect in Micromachin-ing:a FEM Simulation Approach[J]. Journal of Ma-terials Processing Technology, 2008,195 ( 1/3 ) : 204- 211.
[5]
Taylor G I. The Mechanism of Plastic Deformation of Crystals. Part I. Theoretical [J]. Proceedings ofthe Royal Society of London, Series A, 1934, 145,362-387.
[6]
Liu K. Processes Modeling of Micro--cutting Including Strain Gradient Effects [D]. Georgia: GeorgiaInstitute of Technology, 2005.
[7]
Tabor D. The Hardness of Metals[M]. Oxford: Ox-ford University Press, 2000.
2011, Vol. 22 
