Three-dimensional modeling of plastic deformation flow during ECAP
- Igor V.
- Irene Jane
- Yu V.
Plastic flow during equal-channel angular pressing (ECAP) of a copper billet is analyzed in this paper using three-dimensional finite element. The influence of the outer die radius and friction coefficient on the homogeneity in the accumulated plastic strain distribution is investigated. An increase in either outer radius or friction conditions was found to decrease the size of the steady-state region and increase heterogeneity in the final strain distribution from top to bottom and from side to side. Recent investigations have clearly demonstrated the great potential of the severe plastic deformation (SPD) methods, particularly by means of equal-channel angular pressing (ECAP), for ultra-fine grain refinement in various metals and alloys. One of the biggest challenges faced is the fabrication of larger and larger bulk ECAP samples with a uniform desired microstructure, e.g. equiaxed ultra-fine grains, and hence outstanding mechanical properties characteristic of such SPD materials. The degree of homogeneity depends on a myriad of processing and material variables. Numerical methods, such as finite elements (FE), have been an important tool in simulating the ECAP process and exploring the large ECAP parameter space, such as the pressing route and number of passes, die channel intersection angle, outer radius of the die, friction coefficient, pressing rate, material deformation response, and backpressure, e.g. Studying the effects of several factors simultaneously, however, can potentially lead to ambiguous conclusions about the regularities in the plastic flow, regularities in the material fill status, or the final distributions of accumulated total plastic strain. Thus more systematic studies using FE coupled with theoretical considerations are needed. Also, most of the FE studies found in the literature are two-dimensional analyses, and therefore cannot make conclusions regarding the influence of the confined character of plastic deformation on plastic flow in ECAP. In this work, we present preliminary results using a three dimensional (3D) FE code for simulating ECAP. The influence of the outer die radius and friction coefficient on the accumulated plastic strain in a single ECAP pass of pure Cu (99.9%) is investigated. Special attention is paid to the heterogeneity in strain along the billet length, from top to bottom, and side to side. We will also compare the simulated punch force vs displacement curve with the experimental curve to access the accuracy of the material and friction models.
- Research Organization:
- Los Alamos National Laboratory
- Sponsoring Organization:
- DOE
- OSTI ID:
- 977458
- Report Number(s):
- LA-UR-04-0779; LA-UR-04-779
- Country of Publication:
- United States
- Language:
- English
Similar Records
Fatigue-Property Enhancements of Magnesium Alloy, AZ31B, through Equal-Channel-Angular Pressing (ECAP)
Effect of ECAP Die Angles on Microstructure Mechanical Properties and Corrosion Behavior of AZ80 Mg Alloy