Visualization of microstructural mechanisms in nanocrystalline ferrite during grinding. (October 2020)

• Record Type: Journal Article
• Authors: Grützmacher, P.; Gachot, C.; Eder, S.J.
• Is Part Of: Materials & design. Volume 195(2020)
• Publication Date: 2020-10
• Subjects: Microstructure -- EBSD analysis -- Grinding -- Molecular dynamics -- Tribology; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2020.109053
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Microstructural changes in the near-surface regions of a material determine its mechanical properties and consequently also its tribological behavior. This work is a study of the microstructural development of nanocrystalline ferrite subjected to a grinding process using molecular dynamics simulations. We visualize the work piece by producing various types of computational tomographic sections that are colored according to the grain orientation, the local temperature, the stress in grinding direction, as well as the atomic flow velocities. In particular, we introduce "differential EBSD" tomographs to highlight the changes to the microstructure caused by the grinding process, allowing us to detect even subtle differences in lattice orientation and small distances in grain boundary migration. We use our visualization approach to discuss the acting microstructural mechanisms in a load- and time-resolved fashion, spanning a wide range of grinding conditions from mild to severe. In addition to removed matter, we observe lattice rotation originating at the surface and advancing deeper into the work piece with increasing load, grain growth by grain boundary migration, and the transient formation of unstable small new grains. Graphical abstract: Unlabelled Image Highlights: We use large-scale molecular dynamics simulations to model a grinding process of a ferritic work piece. We visualize the microstructural development of a nanocrystalline work piece using time-resolved computational tomography. We introduce "differential EBSD tomography" as a tool to detect subtle changes in the grain structure and orientation. We elucidate the deformation mechanisms occurring during grinding as a function of load.