X-ray diffraction analysis of three-dimensional residual stress fields reveals origins of thermal fatigue in uncoated and coated steel

Synchrotron X-ray diffraction analysis of three-dimensional residual stress fields in laser-pulsed uncoated and CrN-coated steels was performed by a combination of two complementary synchrotron approaches. In the uncoated steel, the measurements revealed crater-like tensile stress distributions close to thermal cracks. For the coated samples, a regular Gaussian distribution was observed for steel whereby a cracking occurs in CrN as a consequence of steel buckling. The data also revealed the mechanism by which hard coatings protect steel from thermal fatigue.