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Abstract
It is known that grain boundaries with differing chemistry, misorientation and structure have varying susceptibility to stress-corrosion cracking (SCC). However, up till now it has not been possible to obtain mechanical property data on individual grain boundaries as they fail under SCC. A novel method of using focused-ion beam machining to manufacture test specimens containing single grain boundaries, combined with loading in a nano-indenter, allows threshold stress levels and crack growth rates in 304 stainless steel to be directly measured. This technique opens up a new field in being able to validate atomistic scale and dislocation models of intergranular SCC. Combining this information with recent advances in microcharacterisastion, modelling and thermomechanical treatment engineering promises to provide a more complete understanding of inter-granular SCC failure and a better approach to reducing SCC susceptibility and predicting component lifetimes.