2025-08-07 ミシガン大学
＜関連情報＞
- https://news.umich.edu/first-3d-look-at-strength-boosting-twinning-behavior-in-lightweight-magnesium-alloy/
- https://www.science.org/doi/10.1126/science.adv3460
マグネシウムにおける変形双晶の三次元核生成と成長 Three-dimensional nucleation and growth of deformation twins in magnesium
Sangwon Lee, Michael Pilipchuk, Can Yildirim, Duncan Greeley, […] , and Ashley Bucsek
Science Published:7 Aug 2025
DOI:https://doi.org/10.1126/science.adv3460
Editor’s summary
Dark-field x-ray microscopy has revealed the three-dimensional details of deformation twinning inside an embedded grain in a bulk, polycrystalline magnesium-aluminum alloy. Lee et al. studied twinning in these lightweight alloys because twins can both accommodate plastic strain and serve as unwanted crack initiation sites. Under applied stress, twins appeared as irregular ellipsoid shapes. The authors studied preferential growth directions and how twinning relates to dislocation accumulation that precedes crack initiation. —Phil Szuromi
Abstract
At two-thirds the weight of aluminum, magnesium alloys have the potential to reduce the fuel consumption of transportation vehicles. These advancements depend on our ability to optimize the desirable versus undesirable effects of deformation twins, which are three-dimensional (3D) microstructural domains that form under mechanical stresses. Previously only characterized through surface or thin-film measurements, we present 3D in situ characterization of deformation twinning inside an embedded grain over mesoscopic fields of view using dark-field x-ray microscopy supported by crystal plasticity finite element analysis. The results revealed the role of triple junctions on twin nucleation and the sequence and irregularity of twin growth and showed that twin-grain junctions, twin-twin junctions, and twin boundaries were the sites of localized dislocation accumulation.
