Competition mechanisms of fatigue crack growth behavior in lath martensitic steel

• DOI: 10.1111/ffe.12851
• Publication Date: 2018-06-06T08:00:17Z
• Authors: M. Yang; Y. Zhong; Y.‐l. Liang
• Keywords: Lath; Paris' law; Substructure

Abstract The fatigue crack growth behavior in 20CrMnTi lath martensitic steel with a hierarchical structure was investigated at room temperature. microstructure quantitatively characterized by optical microscopy, scanning electron backscattering diffraction, and transmission microscopy. Crack tests were performed stress ratio of 0.1 under the control intensity factor range using compact tension specimens. results show that martensite medium grain size quenched ice salt water possessed highest propagation resistance, which attributed to relatively high intrinsic resistance extrinsic resistance. Meanwhile, indicate increased size, while showed an inverse tendency. In addition, effect substructure on properties is discussed. deflection angle block interfaces path indicated unit had significant steel. Based Taylor model, (d b ) considered be effective for controlling threshold value (∆K th ).