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Title: Applications of Computer Simulation Methods in Plastic Forming Technologies for Magnesium Alloys

Abstract

Applications of computer simulation methods in plastic forming of magnesium alloy parts are discussed. As magnesium alloys possess very poor plastic formability at room temperature, various methods have been tried to improve the formability, for example, suitable rolling process and annealing procedures should be found to produce qualified magnesium alloy sheets, which have the reduced anisotropy and improved formability. The blank can be heated to a warm temperature or a hot temperature; a suitable temperature field is designed, tools should be heated or the punch should be cooled; suitable deformation speed should be found to ensure suitable strain rate range. Damage theory considering non-isothermal forming is established. Various modeling methods have been tried to consider above situations. The following situations for modeling the forming process of magnesium alloy sheets and tubes are dealt with: (1) modeling for predicting wrinkling and anisotropy of sheet warm forming; (2) damage theory used for predicting ruptures in sheet warm forming; (3) modeling for optimizing of blank shape and dimensions for sheet warm forming; (4) modeling in non-steady-state creep in hot metal gas forming of AZ31 tubes.

Authors:
; ;  [1];  [2]; ;  [3]
  1. Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016 (China)
  2. Wayne State University, Detroit, MI 48202 (United States)
  3. Polytechnic of Bari, Bari, 70126 (Italy)
Publication Date:
OSTI Identifier:
21061724
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 908; Journal Issue: 1; Conference: NUMIFORM 2007: 9. international conference on numerical methods in industrial forming processes, Porto (Portugal), 17-21 Jun 2007; Other Information: DOI: 10.1063/1.2740867; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; ANNEALING; COMPUTERIZED SIMULATION; CREEP; DEFORMATION; MAGNESIUM ALLOYS; METALS; OPTIMIZATION; PLASTICITY; PROCESS CONTROL; ROLLING; RUPTURES; SHEETS; STEADY-STATE CONDITIONS; STRAIN RATE; VELOCITY

Citation Formats

Zhang, S. H., Zheng, W. T., Shang, Y. L., Wu, X., Palumbo, G., and Tricarico, L.. Applications of Computer Simulation Methods in Plastic Forming Technologies for Magnesium Alloys. United States: N. p., 2007. Web. doi:10.1063/1.2740867.
Zhang, S. H., Zheng, W. T., Shang, Y. L., Wu, X., Palumbo, G., & Tricarico, L.. Applications of Computer Simulation Methods in Plastic Forming Technologies for Magnesium Alloys. United States. doi:10.1063/1.2740867.
Zhang, S. H., Zheng, W. T., Shang, Y. L., Wu, X., Palumbo, G., and Tricarico, L.. Thu . "Applications of Computer Simulation Methods in Plastic Forming Technologies for Magnesium Alloys". United States. doi:10.1063/1.2740867.
@article{osti_21061724,
title = {Applications of Computer Simulation Methods in Plastic Forming Technologies for Magnesium Alloys},
author = {Zhang, S. H. and Zheng, W. T. and Shang, Y. L. and Wu, X. and Palumbo, G. and Tricarico, L.},
abstractNote = {Applications of computer simulation methods in plastic forming of magnesium alloy parts are discussed. As magnesium alloys possess very poor plastic formability at room temperature, various methods have been tried to improve the formability, for example, suitable rolling process and annealing procedures should be found to produce qualified magnesium alloy sheets, which have the reduced anisotropy and improved formability. The blank can be heated to a warm temperature or a hot temperature; a suitable temperature field is designed, tools should be heated or the punch should be cooled; suitable deformation speed should be found to ensure suitable strain rate range. Damage theory considering non-isothermal forming is established. Various modeling methods have been tried to consider above situations. The following situations for modeling the forming process of magnesium alloy sheets and tubes are dealt with: (1) modeling for predicting wrinkling and anisotropy of sheet warm forming; (2) damage theory used for predicting ruptures in sheet warm forming; (3) modeling for optimizing of blank shape and dimensions for sheet warm forming; (4) modeling in non-steady-state creep in hot metal gas forming of AZ31 tubes.},
doi = {10.1063/1.2740867},
journal = {AIP Conference Proceedings},
number = 1,
volume = 908,
place = {United States},
year = {Thu May 17 00:00:00 EDT 2007},
month = {Thu May 17 00:00:00 EDT 2007}
}
  • In this paper, a constitutive framework based on a crystalline plasticity model is employed to simulate the plastic deformation of AZ31 magnesium alloy, which posses the hexagonal close packed (HCP) crystal structure. Dislocation slip and mechanical twinning are taken into account in the model. The successive integration method is used to determine the active slip systems, and the contribution of twinning to the grain reorientation is treated by the PTR method. The FE model is introduced into ABAQUS/Explicit through a user material subroutine (VUMAT). Three deformation processes of AZ31 magnesium alloy, including tension, compression and a stamping process, are simulatedmore » with the present method. The simulation results are compared with experiment and those presented in the literature.« less
  • Hexagonal close-packed (hcp) metals show a deformation behavior, which is quite different from that of materials with cubic crystalline structure. As a consequence, rolled or extruded products of magnesium and its alloys exhibit a strong anisotropy and an unlike yielding in tension and compression. Microstructural mechanisms of deformation in pure magnesium are modeled by constitutive equations of crystal plasticity. Single crystals and textured polycrystals are analyzed numerically. By means of virtual mechanical tests of representative volume elements mesoscopic yield surfaces are generated and compared with phenomenological yield surfaces. The hardening behavior as well as deformation kinematics are accounted while fittingmore » the respective model parameters for a plane stress state. The linking of micro- and mesoscale provides a procedure for the simulation of the yielding and hardening behavior of arbitrarily textured solids with hcp structure such as extruded bars or rolled plates.« less
  • It is well known that one of the main advantages of the high speed forming (HSF) processes is the improvement in the forming limits of the used materials.Using the Electromagnetic Forming (EMF) technology two materials have been tested with different mechanical and physical properties: the AA5754 aluminium and the AZ31B magnesium alloys.The EMF process principle can be described as follows: A significant amount of electrical energy is stored in a bank of capacitors which are suddenly discharged releasing all the stored energy. This electric discharge runs through a coil which generates an intense transient magnetic field. At the same timemore » transient Eddy currents are induced in the electrically conductive part placed some millimetres far from the coil. Another intense magnetic field is generated due to those Eddy currents but on the opposite direction as the one generated by the coil. A big magnetic repulsion force is created between the part and the coil. This magnetic repulsion between both fields is used to launch the blank with no physical contact and obtain the desired deformation on it.The Forming Limit Diagrams (FLD) obtained in the EMF experiments were them compared to the ones obtained with the 'Nakazima' method at conventional deformation speed for both alloys. In parallel to these physical experiments, some simulations were carried out. But trying to simulate this process by FEM is a though work. There are several physics and many factors to take into account in a few microseconds deformation process. And all these factors are tightly related with each other, that is why to this date there is no commercial software able to simulate the EMF process accurately.From LABEIN-Tecnalia we are working with to different softwares to simulate the whole process: Maxwell 3D for the electromagnetic part and PAM-STAMP2G for the mechanical part of the problem.« less
  • In this work, an implicit, backward Euler time integration scheme is developed for an anisotropic, elastic-plastic model based on strain-rate potentials. The constitutive algorithm includes a sub-stepping procedure to deal with the strong nonlinearity of the plastic potentials when applied to FCC materials. The algorithm is implemented in the static implicit version of the Abaqus finite element code. Several recent plastic potentials have been implemented in this framework. The most accurate potentials require the identification of about twenty material parameters. Both mechanical tests and micromechanical simulations have been used for their identification, for a number of BCC and FCC materials.more » The impact of the identification procedure on the prediction of ears in cup drawing is investigated.« less