Crack nucleation and propagation in Ni-based and Ti-based alloys with different ratios σ –1 /σ 0.2

作     者：Andrey A. Shanyavskiy Alexey P. Soldatenkov 

作者机构：Institute for Computer Aided Design 2nd Brestskaya street 19/18 Moscow 123056 Russia Aviation Register for the Russian Federation Airport Sheremetievo-1 PO Box 54 Moscow region Chimkinskiy State 141426 Russia 

出 版 物：《International Journal of Fatigue》 (Int J Fatigue)

年 卷 期：2025年第200卷

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：Russian Science Foundation, RSF, (N23-19-00640) Russian Science Foundation, RSF 

主　　题：Crack origination Cyclic hardening Fatigue Fractography Slip bands 

摘      要：The behavior of metals in both low-cycle (LCF) and high-cycle fatigue (HCF) regimes is considered using Ni-based (grade EI698) and Ti-based (grade VT22) alloys. It is shown that the mechanism characterizing the crack initiation in the LCF regime by persistent slip band formation does not correspond to the crack initiation mechanism in the HCF one. Data on the relationship between the yield stress and the fatigue limit of structural materials are generalized and it is revealed that in more than 95 % of metals, the fatigue limit is lower than the yield stress. The regularities of the evolution of hysteresis loops in the EI986 alloy with an increase in the number of loading cycles when fracture occurs under LCF regime are shown, and the absence of hysteresis loops in the VT22 alloy, fractured under HCF regime, is shown at the approximately similar number of cycles. The regularities of fracture relief formation in both alloys are studied, and kinetic curves are plotted by using the measured fatigue striation spacings. A generalized fatigue failure diagram is demonstrated, which, at a ratio of σ –1 /σ 0.2 ≥ 1, coincides with the previously proposed by Mughrabi, which explains the nature of the subsurface fracture origin formation.