Quantitative measurement of displacement and strain fields in the ZrO2 layer during the transition to nodular oxidation

► Microstructure of nodular oxide formed on Zr alloy was characterized using HRTEM. ► Strain field in the ZrO2 layer was measured quantitatively using GPA method. ► The stress built up in the oxide has a huge impact on onset of nodular oxidation. ► A number of dislocations in nodular oxide were caused by plastic deformation. ► The growth mechanism of nodular Zr oxide is proposed.