Analysis of fatigue performance of austenitic stainless steels with bimodal harmonic structures based on multiscale model simulations. (February 2023)

• Record Type: Journal Article
• Authors: Zhou, Hongchang; Liu, Zijie; Kikuchi, Shoichi; Shibanuma, Kazuki
• Is Part Of: Materials & design. Volume 226(2023)
• Publication Date: 2023-02
• Subjects: Fatigue -- Austenitic stainless steels -- Harmonic structure -- Multiscale model; HS harmonic structure -- CG coarse-grain, coarse-grained -- UFG ultra-fine grain, ultra-fine grained -- FEA finite element analysis -- IPF inverse pole figure -- EBSD electron backscatter diffraction -- OIM orientation imaging microscopy -- GB grain boundary -- S–S stress–strain -- RPGM reconstructed periodic grain -- RVE representative volume element -- MM mechanical milling; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2023.111657
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Austenitic stainless steel with harmonic structure (HS) were analysed considering fatigue performance using multiscale model simulations. A method is proposed to characterise the microstructural features of HS materials considering coarse grain and ultra-fine grain distributions. A multiscale model is developed to simulate the fatigue behaviour of harmonic structure material. The multiscale model was validated by experimental results. This study provides the initial approach to quantitatively design the fatigue performance of HS materials rather than expensive experimental analyses. Abstract: Austenitic stainless steel with a bimodal harmonic structure (HS) is a recently developed material that consists of a periodic arrangement of coarse-grained (CG) structures surrounded by a network of ultra-fine grains (UFG). This material is characterised by high strength and good ductility. In this study, we analysed the fatigue performance of HS materials by modifying our previous multiscale model to extend its applicability from only homogeneous materials to HS materials. A novel method was proposed to characterise the microstructural features of HS materials considering the distributions of CG and UFG. A microstructure model was developed to reproduce grain maps using these characterised microstructures. The multiscale model was successfully validated by experimental results for two types of austenitic stainless steels. The model was used to elucidate the governing microstructural factors of fatigue performance in HS materials through systematic simulations. Consequently, a higher UFG area fraction was confirmed to improve fatigue life, and a UFG area fraction of approximately 40% is suggested for optimal microstructural design to balance fatigue performance and fabricating costs. This study presents the first step in the qualitative design of the fatigue performance of HS materials to replace the expensive and inefficient experimental analyses used in previous studies.