Effect of boundaries on toughness in high-strength low-alloy steels from the view of crystallographic misorientation

摘要

An abnormal variation of ductile-to-brittle transition temperature (DBTT) with density of high angle grain boundaries (HAGBs) was found in a high-strength low-alloy (HSLA) steel. Further analysis on special misorientation angle (SMA) indicates that HAGBs always have high SMA between {1 0 0}-planes, but do not definitely have high SMA between {1 1 0}-planes. When the boundaries were quantitatively recounted according to the SMA, the sample with lower DBTT exhibited higher density of boundaries with higher SMA between {1 1 0}-planes. Therefore, the density of HAGBs could not reflect the change of DBTT sufficiently, DBTT was essentially influenced by the distribution of SMA between {1 0 0}planes and SMA between {1 1 0}-planes. (C) 2019 Published by Elsevier B.V.