Severe Plastic Deformation by Machining Characterized by Finite Element Simulation

A finite element model of large strain deformation in machining is presented in the context of using machining as a controlled method for severe plastic deformation (SPD). Various characteristics of the large strain deformation field associated with chip formation, including strain, strain distribution, strain rate, and velocity field, are calculated using the model and compared with direct measurements in plane strain machining. Reasonable agreement is found for all cases considered. The versatility and accuracy of the finite element model are demonstrated, especially in the range of highly negative rake angles, wherein the shear plane model of machining is less applicable due to the nature of material flow around the tool cutting edge. The influence of the tool rake angle and friction at the tool-chip interface on the deformation is explored and used to establish correspondences between controllable machining input parameters and deformation parameters. These correspondences indicate that machining is a viable, controlled method of severe plastic deformation. Implications of the results for creation of nanostructured and ultra-fine-grained alloys by machining are briefly highlighted.