Ensuring the strength and ductility synergy in an austenitic stainless steel: single- or multi-phase hetero-structures design

SCRIPTA MATERIALIA

卷:193

Article

Li, Yong^1,2  Li, Wei^1,2  Li, Shilei³  Min, Na⁴  Jiang, Laizhu⁵  Zhou, Qinglong⁵  Jin, Xuejun^1,2 

[1] Shanghai Jiao Tong Univ, Shanghai Key Lab Mat Laser Proc & Modificat, Shanghai 200240, Peoples R China

[2] Shanghai Jiao Tong Univ, Inst Adv Steels & Mat, Sch Mat Sci & Engn, Shanghai 200240, Peoples R China

[3] Univ Sci & Technol Beijing, Beijing Adv Innovat Ctr Mat Genome Engn, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China

[4] Shanghai Univ, Key Lab Microstruct, Shanghai 200444, Peoples R China

[5] Res Inst Tsingtuo Grp Co Ltd, Fuan 355006, Peoples R China

关键词: Heterogeneous microstructure;    Transformation-induced plasticity;    Twinning-induced plasticity;    Dislocation;   

DOI  :  10.1016/j.scriptamat.2020.10.041

来源: Elsevier

【 摘 要 】

Heterogeneous microstructures have been proposed to optimize the mechanical properties in the re-spect of strength and ductility synergy in many alloy systems. In this work, the multi-phase heterostructured microstructure consisting of fine grains and coarse grains where the ferrite is embedded in the vicinity of the nano-grains was obtained by regulating the thermomechanical processing parameters. A yield strength of 1.2 GPa which is more than two times higher than the coarse grained counterpart with less uniform elongation loss is achieved in the multi-phase hetero-structured steel. The microscopic load transfer in this complex microstructure is investigated by the in situ high energy synchrotron X-ray diffraction. The persistent strain hardening is ascribed to the hetero-deformation induced stress associated with the joint activation of transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) effects. As a comparison, the single-phase hetero-structured steel exhibits little lower strength but higher uniform ductility. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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