文献类型：期刊文献

英文题名：Influence of DIMT on impact toughness: Relationship between crack propagation and the α′-martensite morphology in austenitic steel

作者：Huang, Minghao[1]; Wang, Chenchong[1]; Wang, Lingyu[1]; Wang, Jinliang[2]; Mogucheva, Anna[3]; Xu, Wei[1]

机构：[1] State Key Laboratory of Rolling and Automation, School of Materials Science and Engineering, Northeastern University, Shenyang, 110819, China; [2] School of Mechanical and Power Engineering, Guangdong Ocean University, Zhanjiang, 524000, China; [3] Laboratory of Mechanical Properties of Nanoscale Materials and Superalloys, Belgorod State University, Belgorod, 308015, Russia

年份：2022

卷号：844

外文期刊名：Materials Science and Engineering: A

收录：EI(收录号：20221812056938)、Scopus(收录号：2-s2.0-85128997793)

语种：英文

外文关键词：Austenite - Austenitic stainless steel - Austenitic transformations - Crack propagation - Deformation - Economic and social effects - Grain size and shape - High strength steel - Martensite - Morphology - Plasticity

外文摘要：The trade-off between transformation-induced plasticity (TRIP) strengthening and the intrinsically brittle nature of deformation-induced α′-martensite (DIM) has been a long-standing dilemma in optimizing the strength–toughness synergy of austenitic steels. This has limited their potential use, particularly in energy absorption applications. Here, we propose a new strategy to minimize the negative effect of intrinsically brittle α′-martensite without limiting the TRIP. In this study, austenitic 321 stainless steel samples with different austenite grain sizes (AGSs) were fabricated to tailor the DIM morphology. The effect of the DIM morphology on the crack propagation energy was simultaneously evaluated. Electron channeling contrast imaging (ECCI) and selected area electron backscattered diffraction (EBSD) of the Charpy fractures reveals that lath-like α′-martensite effectively deflects cracks and increases the crack propagation energy (Ep). As a consequence, coarse-grained and ultra-coarse-grained (CG/UCG) steels with lath-like α′-martensite can simultaneously achieve high strength and crack propagation resistance, while ultra-fine-grained (UFG) steel with blocky DIM exhibits the lowest Ep. Furthermore, the morphology of DIM is controlled by its nucleation sites and adjacent crystallographic/phase boundaries. The twins or Ε-γ boundaries promote the formation of lath-like α′-martensite. The γ→Ε→α′ transformation sequence can be explained by the change in stacking fault energy (SFE), which provides further guidance for the design of austenitic steels with high strength and high toughness. ? 2022 Elsevier B.V.