Evaluation of the interfacial shear strength and residual stress of TiAlN coating on ZIRLO™ fuel cladding using a modified shear-lag model approach

• Published in: Journal of nuclear materials Vol. 466; no. C; pp. 718 - 727
• Main Authors: Liu, Y., Bhamji, I., Withers, P.J., Wolfe, D.E., Motta, A.T., Preuss, M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2015; Elsevier
• Subjects: Accident tolerant fuels (ATF); ATF (accident tolerant fuel) coating; Cladding; Coating; Fission; Fuels; Interfacial shear strength; Mathematical models; Metal-coating interface; Micromechanical modelling; Residual stress; Titanium aluminum nitride; Zirconium; Zirconium base alloys; Micromechanical modelling; Accident tolerant fuels (ATF); Zirconium; ATF (accident tolerant fuel) coating; Metal-coating interface; Fission
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2015.06.003

This paper investigates the residual stresses and interfacial shear strength of a TiAlN coating on Zr–Nb–Sn–Fe alloy (ZIRLO™) substrate designed to improve corrosion resistance of fuel cladding used in water-cooled nuclear reactors, both during normal and exceptional conditions, e.g. a loss of coolant event (LOCA). The distribution and maximum value of the interfacial shear strength has been estimated using a modified shear-lag model. The parameters critical to this analysis were determined experimentally. From these input parameters the interfacial shear strength between the TiAlN coating and ZIRLO™ substrate was inferred to be around 120 MPa. It is worth noting that the apparent strength of the coating is high (∼3.4 GPa). However, this is predominantly due to the large compressive residuals stress (3 GPa in compression), which must be overcome for the coating to fail in tension, which happens at a load just 150 MPa in excess of this.