Enhanced ductility and reduced asymmetry ofMg-2Al-1Zn alloy plate processed by torsion and annealing
(1. Key Laboratory of Nonferrous Metal Materials Science and Engineering,
School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Institute for Frontier Materials, Deakin University, Geelong 3125, Australia;
3. The University of Electro-Communications, Tokyo 182-8585, Japan)
School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Institute for Frontier Materials, Deakin University, Geelong 3125, Australia;
3. The University of Electro-Communications, Tokyo 182-8585, Japan)
Abstract: The ductility and plastic asymmetry of an as-annealed magnesium alloy plate were studied in compression through combined process of torsion and subsequent annealing by optical microscope and EBSD. The yield strength (YS) and ultimate compression strength (UCS) as well as the compression ductility (CD) were simultaneously raised by prior torsion at room temperature. The CD was further enhanced by subsequent annealing. Also, the torqued sample followed by annealing experienced a rising CD with the increase in prior strain, leading to the maximum true strain of 0.279, which is twice that of the as-annealed original one. The sample showed a largely reduced tension-compression yield asymmetry by subjecting to pre-torsion alone or combined with a subsequent annealing. The enhanced ductility and reduced asymmetry are attributed to the development of a gradient microstructure with refined grains, and also randomization of the weakened texture due to torsion and subsequent annealing.
Key words: magnesium alloy; microstructure; torsion; asymmetry; texture; twinning