In the case of plane deformation, the stress-strain of the workpiece can be calculated analytically with some simplifications without losing the generality of the problem. Numerical simulation by DEFORM software can be used to analyze most thermo-mechanical forming processes, and many heat treatment processes. The sequentially simulate each process that is to be applied to the workpiece of Constrained Grooved Pressing (CGP) plastic deformation process by finite element method allows to determine technological parameters such as pressure force, stress field, strain field and risk of failure or destruction. The stress-strain has been analyzed at the characteristic points of the plastic deformation region including on the surface, at the center of the workpiece and at the transition regions, the results are consistent with the theoretical study. The unique feature of CGP technology compared to other types of severe plastic deformation (SPD) is that the plastic deformation zone is not in a direct contact with the mold surface, but subjected to indirect forces, and has a small hydrostatic stress. The hydrostatic force and stress parameters only come into play at the end of the back elastic compression stroke. Through numerical simulation, it is possible to visually determine the state of stress and strain on the entire workpiece at all times of the stroke. Therefore, it is possible to determine the stress in the principle axis system.
A magnesium alloy AZ31 as plate of dimensions (60 x 60 x 3) mm has been constrained groove pressed (CGP) four deformation passes (16 pressings) at 250 oC by simulation and experiments. On the basis of the analysis of calculation results about the deformation distribution in the alloy AZ31 workpieces, the mechanism for its microstructure evolution during the severe plastic deformation (SPD) process was partly clarified. On the other hand, deformation heterogeneity distribution developed in the workpieces by applying CGP caused the evolution of a non-uniform microstructure. The TEM microstructure analysis results provided clear evidence that across the plate both the banded deformed microstructure where dislocation cell structure and/or partially or fully recovered polygonized subgrain microstructure are present. The recovering dynamic and local polygonization process contributes significantly to the formation of ultra-fine materials (UFG) microstructure.
This study the AZ31 magnesium alloy trips of the dimension 60×60×3 mm was used for constrained groove pressing (CGP) after 4 cycles under elevated temperature condition. Microstructure and mechanical properties were analyzed for a material with ultra-fine grained structure prepared by CGP of AZ31 magnesium alloy. Analysis of the scanning electron microscope (SEM) micrographs observations showed significant drop of the grain size from (50 ÷ 60) μm to (4 ÷ 6) μm after four CGP cycles. The minimal grain size of (H1.5) μm was detected in the regions of the highest deformation. Moreover, the tensile test along the x and z directions showed excellent high strength (325 MPa) and also plastic elongation of 35 %. It is shown that the CGP technique is a good tool for the grain refinement and improving mechanical properties of magnesium alloys.
A magnesium alloy AZ31 as plate of dimensions (60 x 60 x 3) mm has been constrained groove pressed (CGP) four deformation passes (16 pressings) at 250 oC by simulation and experiments. On the basis of the analysis of calculation results about the deformation distribution in the alloy AZ31 workpieces, the mechanism for its microstructure evolution during the severe plastic deformation (SPD) process was partly clarified. On the other hand, deformation heterogeneity distribution developed in the workpieces by applying CGP caused the evolution of a non-uniform microstructure. The TEM microstructure analysis results provided clear evidence that across the plate both the banded deformed microstructure where dislocation cell structure and/or partially or fully recovered polygonized subgrain microstructure are present. The recovering dynamic and local polygonization process contributes significantly to the formation of ultra-fine materials (UFG) microstructure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.