Influence of plastic deformation in fatigue crack behavior in bainitic steel. (February 2021)

• Record Type: Journal Article
• Authors: Marinelli, M.C.; M.Balbi, ; Krupp, U.
• Is Part Of: International journal of fatigue. Volume 143(2021)
• Publication Date: 2021-02
• Subjects: LCF -- Surface crack initiation -- Crack propagation -- High strength bainitic steel; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2020.106014
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: Fatigue crack behavior is investigated by in-situ observation and analyzed by EBSD. Dislocation structure is analyzed and correlated with microstructural crack. Bilinearity in the Coffin-Manson relationship at Δεp = 0.2% Effect of plastic strain about changes in the crack initiation and propagation mode. High twist angle presents larger resistance to crack propagation than a tilt angle. Abstract: In the present paper, the behavior of fatigue microcracks is studied in a high-strength bainitic steel with the aim of identifying the microstructural features that influence the mode of initiation and propagation of microcracks. For this study, a gradual monitoring of surface damage during low-cycle fatigue test at different plastic strain ranges was carried out by means of light optical and electron microscopy along with EBSD data analysis. Moreover, the dislocation structure near the surface was analyzed and correlated with the crack initiation site. The results showed a change with respect to cracking mechanisms from 0.2% plastic strain.