In Situ Characterization of Deformation Twinning in Magnesium During Cyclic Loading via Electron Backscatter Diffraction

• Published in: JOM (1989) 2022-07, Vol.74 (7), p.2577-2591
• Main Authors: Chen, Zhe, Torbet, Chris, Allison, John
• Format: Article
• Language: English
• Subjects: Algorithms; Alloys; Asymmetry; Chemistry/Food Science; Crystallography; Cyclic loads; Deformation; Earth Sciences; Electron backscatter diffraction; Engineering; Environment; Grain orientation; Identification; In-situ Methods for Understanding Deformation & MS Evolution in Mg Alloys; Magnesium; Materials Science; Metallurgy & Metallurgical Engineering; Microscopy; Mineralogy; Mining & Mineral Processing; Physics; Software
• ISSN: 1047-4838; 1543-1851
• DOI: 10.1007/s11837-022-05335-8

An approach for identifying deformation twinning and twin variants from electron backscatter diffraction (EBSD) data collected at multiple load steps during in situ cyclic loading of a Mg-4Al alloy is introduced. After initial clean up by OIM Analysis TM software, the EBSD maps of different load steps were spatially transformed and aligned, compared, and modified to have a consistent grain definition throughout all load steps. For each grain, the parent orientation at different load steps was determined with the EBSD data at the undeformed load step as reference, and the twins were identified by comparing the child grain orientation with each possible twin variant orientation of the parent grain. Special attention was paid to the calculation of crystallographically equivalent orientations and grain average orientation, which is essential for making the twin variant identification consistent throughout all load steps. The twin identification methodology was used to visualize the twin evolution history during cyclic loading, including investigation of the behavior of persistent twins.