13th International Conference on Fracture June 16–21, 2013, Beijing, China -7- 0 1 2 3 4 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 uniaxial tension bending SCF a/2c 0 200 400 600 800 1000 1200 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 uniaxial tension bending 2c=1000μm SCF (a) SCF (2c) a, 2c(μm) a=100μm Fig. 4 SCF variation with a/2c Figure. Fig.5 SCF variation with 2c and a 3) Cracks do not necessarily originate from the bottom of the pit. Rather, it starts from the point which has the biggest SCF. The aspect ratio affects the SCF greatly when a/2c is less than 1 but almost has no effect when a/2c is greater than 2. The pit depth has much bigger effect on SCF than the pit width does. Acknowledgements The authors would like to thank National Science Foundation of China (No. 51275225) for financial support and PHD foundation of Lanzhou University of Technology (SB05200801) for which due acknowledgement is given. References [1]Sriraman M R, Pidaparti R M, Crack initiation life of materials under combined pitting corrosion and cyclic loading. J. Mater. Eng. Performance, 19 (2010) 7-12. [2]Boag A, Taylor R J, Muster T H, Goodman N, McCulloch D, Ryan C, Rout B, Jamieson D, Hughes A E, Stable pit formation on AA2024-T3 in a NaCl environment. Corro. Sci., 52 (2010) 90-103. [3]Ebara R, Corrosion fatigue crack initiation in 12% chromium stainless steel. Mater. Sci. Eng. A, 468–470 (2007) 109-113. [4]Sankaran K K, Perez R, Jata K V, Effects of pitting corrosion on the fatigue behavior of aluminum alloy 7075-T6: modeling and experimental studies. Mater. Sci. Eng.: A, 297 (2001) 223-229. [5]Rybalka K V, Shaldaev V S, Beketaeva L A, Malofeeva A N, Development of pitting corrosion of stainless steel 403 in sodium chloride solutions. Russian J. Electrochem., 46 (2010) 196-204. [6]Rybalka K V, Beketaeva L A, Shaldaev V S, Kasparova L V, Davydov A D, Development of pitting corrosion on 20Kh13 steel. Russian J. Electrochem., 45 (2009) 1217-1225. [7]Ernst P, Newman R C, Pit growth studies in stainless steel foils. I. Introduction and pit growth kinetics. Corro. Sci., 44 (2002) 927-941. [8]Ernst P, Newman R C, Pit growth studies in stainless steel foils. II. Effect of temperature, chloride concentration and sulphate addition. Corro. Sci., 44 (2002) 943-954. [9]Harlow D G, Wei R P, A probability model for the growth of corrosion pits in aluminum alloys induced by constituent particles. Eng. Fract. Mechan., 59 (1998) 305-325. [10]Kondo Y, Prediction of fatigue crack initiation life based on pit growth. Int. J. Fat., 11 (1989) 280.
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