Open AccessThe Coupling of Grain Growth and Twinning in FCC Metals
Author(s) -
Spencer L. Thomas,
Jian Han,
David J. Srolovitz
Publication year - 2019
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/580/1/012026
Subject(s) - crystal twinning , nanocrystalline material , materials science , crystallite , grain boundary , annealing (glass) , molecular dynamics , condensed matter physics , chemical physics , crystallography , chemistry , nanotechnology , metallurgy , physics , microstructure , computational chemistry
Coherent twin boundaries (CTBs) routinely form during the annealing of polycrystalline metals, in the absence of an applied stress. Molecular dynamics (MD) simulations of normal grain growth in nanocrystalline metals show such annealing twins as well the formation of twin junctions. MD simulations and theoretical analyses demonstrate how these junctions form and that their formation necessarily retards grain boundary (GB) migration. Both CTB and GB migration occurs via disconnection motion. We identify the types of disconnections important for CTB migration and show the disconnection pile-ups at TJs during GB migration are responsible for CTB formation in the vicinity of TJs. Analysis further shows that at least two types twinning partials are to be expected during TJ migration and that these give rise to the multiple twinning near migrating TJs observed in the MD simulations.