Stress-Corrosion Cracking 

Stress-Corrosion Cracking 101
 
Pipelines are the most efficient and economical ways to transport oil and natural gas products to marketplaces. However, gas pipeline failures pose significant safety threats and will be of increasing concern due to aging infrastructure and expense of new construction. Stress Corrosion Cracking (SCC) from the external surface of a pipeline is one of the primary degradation modes in oil and gas pipelines. SCC refers to the failure by cracking of normally ductile metals in corrosive environments, when they are subject to tensile stress.
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Tensile stress and plastic deformation in aluminum induced by aqueous corrosion
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The electrochemical driving force for vacancy diffusion-induced tensile stress and plasticity during SCC in aluminum was investigated by combining stress measurements,  spectrul analysis of SEM images and morphological stability analysis. 

It is found that corrosion processes can produce defective and presumably weakened surface layers that may be precursors for crack initiation. Detection of such layers can provide valuable early indication of SCC susceptibility prior to the catastrophic propagation stage.
Ö. Özgür Çapraz, Shinsuke Ide, Pranav Shrotriya and Kurt Hebert, Electrochim. Acta,  2016, 115, 434–441, doi: 10.1016/j.actamat.2016.05.028, link