Severe Plastic Deformation by Machining Characterized by Finite Element Simulation

Abstract

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 ultrafine-grained alloys by machining are briefly highlighted.

Analysis of Severe Plastic Deformation by Large Strain Extrusion Machining

“…Strain and strain rate fields in the machining deformation zone were measured at high resolution for a range of tool rake angles, from positive to negative. [33,34] The results of the finite element analysis from the prior work, which is similar to that implemented for the LSEM in Figure 2(d) here, showed reasonable agreement with the measurements in all cases. This detailed validation of the analysis by comparison with experimental results [33] provides sufficient confidence for applying it to study the LSEM.…”

“…A similar modeling approach was used by Sevier et al [33] to examine SPD in conventional plane-strain machining, wherein there is no constraint on the chip formation. Strain and strain rate fields in the machining deformation zone were measured at high resolution for a range of tool rake angles, from positive to negative.…”

Parametric optimization for the production of nanostructure in high carbon steel chips via machining

“…The interest in ultra-fine grained materials which exhibit significantly enhanced mechanical properties has been developed and the attention has been focussed on the application of SPD in the view of achieving microstructure refinement in metals and alloys. A commonly used approach for refinement of microstructure in metals and alloys is the SPD [2]. The SPD generally refers to a class of processes wherein a material is deformed to large plastic strains through the use of multiple passes of deformation.…”

A 2D Computer Model of Cutting of the A2024 Aluminum Alloy

“…And it is well known, that big values of strains and temperature might result in recrystalization processes. Tool angle and its speed have great effect on these characteristics [5]. Thus requirements arise for the process parameters, where, for example, temperature should not exceed a maximum value, as it grains will grow.…”