On the microscale deformation of the oxide layer formed on a Zr-2.5 Nb alloy: A micropillar compression study

Oxides are prone to brittle failure, leading to passivity loss and exposing the underlying metal during service. Thus, understanding the mechanical response of oxides is crucial for evaluating metal passivity. The present study examines the oxide layer on a Zr-2.5 Nb alloy used in CANDU (R) reactors after different exposure times. Micropillar compression tests on the oxide layer revealed that the mean failure stress and strain remain unchanged (are within the error) for both samples. Post-deformation characterization confirms that the failure of the oxide layer is brittle and could be pseudo-shear, which is consistent with the critical failure mode for brittle materials.