Dynamic improvement of fatigue strength via local phase transformation in a circumferentially-notched austenitic stainless steel under fully-reversed loading condition. (February 2020)

• Record Type: Journal Article
• Authors: Nagaishi, Naoaki; Okazaki, Saburo; Ogawa, Yuhei; Matsunaga, Hisao
• Is Part Of: Scripta materialia. Number 176(2020)
• Page Start: 126
• Page End: 130
• Publication Date: 2020-02
• Subjects: Austenitic steels -- Fatigue -- Martensitic phase transformation -- Stress concentration; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2019.09.014
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The fatigue limit of a circumferentially-notched austenitic stainless steel exhibited peculiar improvement under fully-reversed loading ( R =−1), as compared with that under tension-tension loading ( R = 0.1), behavior considered to be unconventional in smooth specimens of similar materials. This was attributed to the different cyclic stress-strain responses at the notch-root, where it was almost elastic at R = 0.1, whereas an elasto-plastic response continued up to later stage of the fatigue process at R =−1. Such cyclic plasticity enhanced martensitic transformation locally and resulted in hardening, thereby restricting fatigue crack initiation from the notch-root. Graphical abstract: Image, graphical abstract