caa a22 4500 386336180 CHVBK 20180307111734.0 cr unu---uuuuu 161130e198908 xx s 000 0 eng 10.1557/S0883769400061935 doi S0883769400061935 pii (NATIONALLICENCE)cambridge-10.1557/S0883769400061935 Liaw P.K. Long Fatigue Cracks — Microstructural Effects and Crack Closure [Elektronische Daten] [P.K. Liaw] Fracture mechanics technology is an effective tool for characterizing the rates of fatigue crack propagation. Generally, fatigue crack growth rate (da/dN) in each loading cycle can be presented as a function of stress intensity range (ΔK), where ΔK = K max — K min, K max and K min are the maximum and the minimum stress intensities, respectively. A typical fatigue crack growth rate curve of da/dN versus ΔK can be divided into three regimes, i.e., Stage I (near-threshold), Stage II (Paris), and Stage III (fast) crack growth regions, as shown in Figure 1. Depending on the region of crack growth, fatigue crack growth behavior can be sensitive to microstructure, environment, and loading conditions [e.g., R (load) ratio = K min / K max]. In the nearthreshold region, fatigue crack growth rates are very slow, ranging from approximately 10−10 to 10−8 m/cycle. In this region, the fatigue crack growth rate curve eventually reaches a threshold stress intensity range, ΔK th, below which the crack would not grow or grow at an extremely slow rate. Typically, the value of ΔK th is operationally defined as the stress intensity range which gives a corresponding crack growth rate of 10−10 m/cycle. In the nearthreshold region, the influence of microstructure, environment, and load ratio on the rates of crack propagation is very significant. Copyright © Materials Research Society 1989 MRS Bulletin Cambridge University Press 14/8(1989-08), 25-36 0883-7694 14:8<25 1989 14 MRS https://doi.org/10.1557/S0883769400061935 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/S0883769400061935 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Liaw P.K. NATIONALLICENCE 773 0- MRS Bulletin Cambridge University Press 14/8(1989-08), 25-36 0883-7694 14:8<25 1989 14 MRS CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge