How cracks grow in steel

Stainless steel components can crack when stress or strain is combined with a corrosive environment, attacking the sensitive grain boundaries. In this study, cracks were initiated in stainless steel and their propagation under stress  visualized in situ, using the 3D grain mapping technique based on diffraction
contrast tomography.

Image of grains in a stainless steel wire showing in red the cracks following joints between grains (Image credit: A. King, copyright 2008 A. King).

Further information:

• Video: Cutting away the sample to show the the crack inside the wire (MPEG, 2,5 mb); Fading in the grain map, to show the grain structure of the sample (MPEG, 0,6 mb); The sample, now transparent, with the crack shown in red. (MPEG, 1,4 mb)
• ESRF news item: Stress corrosion cracking studied with grain mapping by diffraction contrast tomography
• Ref.: A. King et al., Science 321, 382 (2008).