Electron backscatter diffraction

About: Electron backscatter diffraction is a research topic. Over the lifetime, 15184 publications have been published within this topic receiving 317847 citations. The topic is also known as: EBSD.

Resolution of impact-related microstructures in lunar zircon: A shock-deformation mechanism map

Abstract: – The microstructures of lunar zircon grains from breccia samples 72215, 73215, 73235, and 76295 collected during the Apollo 17 mission have been characterized via optical microscopy, cathodoluminescence imaging, and electron backscatter diffraction mapping. These zircon grains preserve deformation microstructures that show a wide range in style and complexity. Planar deformation features (PDFs) are documented in lunar zircon for the first time, and occur along {001}, {110}, and {112}, typically with 0.1–25 μm spacing. The widest PDFs associated with {112} contain microtwin lamellae with 65°/ misorientation relationships. Deformation bands parallel to {100} planes and irregular low-angle ( misorientation axes. This geometry is consistent with a dislocation glide system with {010} during dislocation creep. Nonplanar fractures, recrystallized domains with sharp, irregular interfaces, and localized annealing textures along fractures are also observed. No occurrences of reidite were detected. Shock-deformation microstructures in zircon are explained in terms of elastic anisotropy of zircon. PDFs form along a limited number of specific {hkl} planes that are perpendicular to directions of high Young’s modulus, suggesting that PDFs are likely to be planes of longitudinal lattice damage. Twinned {112} PDFs also contain directions of high shear modulus. A conceptual model is proposed for the development of different deformation microstructures during an impact event. This “shock-deformation mechanism map” is used to explain the relative timing, conditions, and complexity relationships between impact-related deformation microstructures in zircon.

Critical role of scan strategies on the development of microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing

Abstract: Laser based powder bed fusion additive manufacturing offers the flexibility to incorporate standard and user-defined scan strategies in a layer or in between the layers for the customized fabrication of metallic components. In the present study, four different scan strategies and their impact on the development of microstructure, texture, and residual stresses in laser powder bed fusion additive manufacturing of a nickel-based superalloy Inconel 718 was investigated. Light microscopy, scanning electron microscopy combined with electron backscatter diffraction, and neutron diffraction were used as the characterization tools. Strong textures with epitaxially grown columnar grains were observed along the build direction for the two individual scan strategies. Patterns depicting the respective scan strategies were visible in the build plane, which dictated the microstructure development in the other planes. An alternating strategy combining the individual strategies in the successive layers and a 67° rotational strategy weakened the texture by forming finer microstructural features. Von Mises equivalent stress plots revealed lower stress values and gradients, which translates as lower distortions for the alternating and rotational strategies. Overall results confirmed the scope for manipulating the microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing by effectively controlling the scan strategies.

Microtexture evolution via deformation twinning and slip during compression of magnesium alloy AZ31

Abstract: The twinning and slip system activities during compression testing at room temperature and 150 °C have been investigated for an AZ31 magnesium alloy. The samples, which were cut from a rolled sheet, were compressed with the compression axis taken at different angles to the sheet normal direction. The electron backscatter diffraction technique in the scanning electron microscope was used to investigate the local texture and microstructure evolution. The plastic deformation of magnesium is controlled by both { 1 0 1 ¯ 2 } ⁡ 〈 1 0 1 ¯ 1 〉 twinning and slip during deformation. Extensive twinning takes place when the sample is loaded perpendicular to the basal plane normals (BPNs). A high work-hardening rate, with very little twinning, is observed for samples loaded parallel to the BPNs. The main features of the stress–strain curves can be explained based on the microstructural and texture data.