First-Principles Studies on Twinnability of Magnesium Alloys: Effects of Yttrium and Lithium on ( 101̄1)[1̄012] Compression Twinning Deformation Processes

• Published in: Metals and materials international pp. 720 - 729
• Main Authors: Won June Kim, Kyeong Hwan Han, Young Joo Lee, Hyungjun Kim, Eok Kyun Lee
• Format: Journal Article
• Language: English
• Published: 대한금속·재료학회 01.07.2018
• Subjects: 재료공학
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-018-0091-x

We investigate the energetics involved in the ( 101̄2)[1̄011] tension and ( 101̄1)[1̄012] compression twinning deformationprocesses in magnesium via fi rst-principles studies. Through identifi cation of structural changes associated with each deformationprocess, we study the energetics of each deformation process and the local instability in the twin boundary region. We observe that the energy barrier in the (10̄11)[̄1012] compression twinning deformation pathway is higher than that inthe ( 101̄2)[1̄011] tension twinning deformation pathway, even though the ( 101̄1) compression twin boundary is more stablethan the ( 101̄2) tension twin boundary. We extend our study to examine the Effects of Y and Li as alloying elements on eachtwinning deformation process. Our calculations predict that the addition of Y causes a reduction in the probability of fractureby an order of magnitude when the twinning deformation occurs and weakening of the resistivity to twinning deformation. However, the Effect of Li addition on the twinning deformations is weaker than that of Y addition. KCI Citation Count: 0