Characterization of Deformation Twins in Meteorites and Dynamically Loaded Ferrous Materials by Means Of Electron Backscatter Diffraction, EBSD

Abstract This work presents a comparison of crystallographic properties of twin bands formed in bcc iron and those formed in iron meteorites (Neumann bands) during high speed deformation identified by means of electron backscatter diffraction (EBSD). Deformation twins were produced in Armco iron and in steel S235 by firing with an AK74 gun and by impact pressure in the drop impact tester. The twin bands of a few micrometers thickness are embedded in the surrounding crystallographically uniformly oriented grain matrix with a misorientation angle of approx. 59° and the Σ3 incidence. The twin system {112}<111> is preferentially activated. The temperature during loading and the grain size have an impact on the extent of twin formation. However, they do not influence the twin system. The findings provide relevant information on the twin formation mechanism in ferrous bcc materials.