Micro-scale fracture experiments on zirconium hydrides and phase boundaries

• Published in: Journal of nuclear materials Vol. 475; pp. 105 - 112
• Main Authors: Chan, H., Roberts, S.G., Gong, J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2016
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2016.03.026

Fracture properties of micro-scale zirconium hydrides and phase boundaries were studied using microcantilever testing methods. FIB-machined microcantilevers were milled on cross-sectional surfaces of hydrided samples, with the most highly-stressed regions within the δ-hydride film, within the α-Zr or along the Zr-hydride interface. Cantilevers were notched using the FIB and then tested in bending using a nanoindenter. Load-displacement results show that three types of cantilevers have distinct deformation properties. Zr cantilevers deformed plastically. Hydride cantilevers fractured after a small amount of plastic flow; the fracture toughness of the δ-hydride was found to be 3.3 ± 0.4 MPam1/2 and SEM examination showed transgranular cleavage on the fracture surfaces. Cantilevers notched at the Zr-hydride interface developed interfacial voids during loading, at loads considerably lower than that which initiate brittle fracture of hydrides.