The respective roles of thermally grown oxide roughness and NiAl coating anisotropy in oxide spallation

► Spallation depends on the local strain level measured with digital image correlation technique. ► Strain localisation was observed to be function of both oxide roughness and anisotropy of the NiAl grains. ► EBSD and SEM were used to obtain a realistic 3D mesh of the microstructure. ► FEA of anisotropic plasticity and oxide roughness shows their strong influence in spallation scatter.