Crack growth mechanism

H.E. Kadir et al Fatigue crack growth mechanisms in high-pressure die-cast magnesium alloy. Metall. Mat. Trans. A 39, 190-205 (2008)... 

H.E. Kadiri et al Identification and modeling of fatigue crack growth mechanisms in a die-cast AM50 magnesium alloy. Acta Mater. 54, 5061-5076 (2006)... 

Structural failures in general occur by a combination of crack initiation followed by subcritical crack growth mechanism such as stress corrosion, fatigue, and creep until a critical crack size is reached. Thus, fracture mechanics is useful in evaluating ac that leads to failure by fracture. The application of fracture mechanics in failure analysis throws light on the progress from subcritical crack growth to fracture, the amount of load... 

Fig. 1.33 The matrix crack growth mechanisms that operate in 2-D CMCs.

Papini M, Femlund G Spelt JK, Effect of crack growth mechanism on the prediction of fracture load of adhesive joints. Comp. Sci. Tech., 52, 1994, 561. 

Figure 7.30. Possible crack growth mechanism. [Adapted, by permission, from Xu X X, Crocrombe A D, Smith P A, Int. J. Fatigue, 16, No.7, 1994, 469-77.]...

Yet, if cyclic fatigue is the dominant crack growth mechanism of cracks, the above-described arguments can be used in an analogous way. 

Figure 14 Schematization of the different CF crack growth mechanisms [13],...

R. Raj and V. K. Varadan, The kinetics of hydrogen assisted crack growth. Mechanisms of Environment Sensitive Cracking of Materials, Univ. of Surrey, UK (P. R. Swarm, F. P. Ford, and A. R. C. Westwood, eds ). The Metals Society, April 1977, p. 426. 

It is also clear that if in the fatigue cycle the applied exceeds the Kj c of the material then fatigue can activate the SCC. If this is the case then SCC becomes the main crack growth mechanism while fatigue is just borrowing the stress needed to activate the process. There are, therefore, a combination of possibilities that are schematizes by the three circles of the Venn diagram [36]. 

Schematization of the different CF crack growth mechanisms. (From Henaff, G. and Petit, J., Corrosion Deformation Interactions CDl 92, T. Magnin, ed., Les Editions de Physique, Paris, France, p. 599,1993.)...

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