Improvement for properties of Mg alloys via deformation twin boundary plasticity

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06783
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural/Functional materials
• Research Institution: National Institute for Materials Science
• Principal Investigator: Somekawa Hidetoshi 国立研究開発法人物質・材料研究機構, 構造材料研究拠点, グループリーダー (50391222)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 材料工学 / マグネシウム / 偏析 / 変形双晶 / 溶質元素 / インデンテーション / 内部摩擦 / 力学特性

Outline of Final Research Achievements

The possibility for enhancing properties via deformation twin plasticity is examined in this study using several Mg binary alloys, which alloying elements are segregated at twin boundaries. The properties of toughness and crack-propagation behavior are found to be influenced by alloying elements for segregation. The alloying element, which has a characteristic for strong bonding to Mg, is a great effective to improve toughness. Damping properties are also influenced by existence in twin boundary and/or segregation behavior. Segregation of alloying elements having low segregation energy plays a role in prevention of decreased damping properties. Since the interface between matrix and twin boundaries becomes the crack-propagation route, twin boundaries are recognized as the harmful factors for Mg. However, by control of bonding behavior between solute and solvent elements at twin boundaries, such boundaries become the effective microstructures for attaining further good properties.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

変形双晶の形成は、マグネシウムの塑性変形を補完する重要な機構であるが、母相と変形双晶界面近傍は、き裂進展経路となることが多く、高靱性化の阻害要因として認知されている。しかし、変形双晶界面に偏析する溶質元素と母相元素との結合状態を制御することは、き裂進展に対する抵抗力の向上をはじめ、特性付与に繋がることを究明した。特に、界面偏析エネルギーを特性改質の識別因子として扱えることは、新規合金開発や更なる双晶界面活用法探索の点から極めて有用である。