Study on the effect of Cr coating on the internal pressure fatigue behavior of zirconium alloy

Existing research and experiments have yielded two divergent conclusions regarding the effect of Cr coatings on the fatigue behavior of zirconium alloys. One study has indicated an increase, while another has demonstrated a conspicuous decrease. In order to support the design, development and engineering application of Cr-coated zirconium alloy cladding, this paper studied on the internal pressure fatigue test experiment at 350°C. The internal pressure fatigue tests were conducted under peak circumferential stress levels of 280 MPa, 300 MPa, 310 MPa and 320 MPa respectively, with uncoated claddings serving as the control. The fatigue-failure cycles of the Cr-coated zirconium alloy under the aforementioned peak circumferential stress were obtained. The experimental findings demonstrated that, in comparison with uncoated claddings, the fatigue life of Cr-coated zirconium alloy claddings was reduced. The mechanisms of crack nucleation, propagation, and failure in Cr-coated zirconium alloy claddings were studied, and four fatigue failure stages were proposed.