Hot deformation behavior of AA6005 modified with CaO-added Mg at high strains

초록

Hot torsion tests were carried out on an AA6005 modified with CaO-added Mg to study its hot deformation behavior. The flow curves indicated that the failure strain of the modified alloy was greater than that of the conventional alloy at low temperature and all strain rates employed in this study. The constitutive analysis was conducted on the effective stress-effective strain data, and the derived activation energy for hot deformation of the modified alloy was lower than that of the conventional alloy. The processing maps were established at various strains, and the power dissipation efficiency increased as the strain increased. The gap between contour lines decreased as the strain increased, indicating that the power dissipation efficiency became more sensitive to the strain. The optimum deformation conditions were determined by comparing the power dissipation efficiency in the processing maps. However, the power dissipation efficiency of the modified alloy was greater than that of the conventional alloy. The observed microstructure demonstrated that the lower activation energy, greater failure strain, and higher power dissipation efficiency were primarily attributed to the different states in the distribution of second phase particles caused by the use of CaO-added Mg. (C) 2018 Published by Elsevier B.V.

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