Abstract:Zirconium alloy cladding materials inevitably undergo hydrogen absorption in the processing and operation process of the reactor, and its static and dynamic mechanical properties are closely related to the hydrogen content. Samples with hydrogen content ranging from 23 μg/g to 132 μg/g were obtained using the method of gas-phase hydrogen charging, and the influence of hydrogen content on static/dynamic mechanical properties of Zr-Sn-Nb-Fe alloy was studied. The results show that the effect of weak hydrogen charging on the ultimate tensile strength, yield strength, and elongation of zirconium alloy is not obvious. There are a large number of dimples on the fracture surface of the tensile sample before and after hydrogen charging, which is a typical ductile fracture. However, the impact toughness of Zr-Sn-Nb-Fe alloy decreases significantly after trace hydrogen charging. The impact sample without hydrogen charging shows the mixed fracture mechanism of ductile fracture and microcleavage fracture. The increase in hydrogen permeability leads to the emergence of hydride, and the deformation of high strain rate under the impact loading condition leads to secondary cracks in the microstructure. The initiation and expansion of the secondary cracks is the main reason for the reduction of the impact toughness.