The microstructure and hydriding characteristics of high temperature aged U–13 at.%Nb alloy

Abstract Niobium as alloying element significantly improves physical and chemical properties of metallic uranium, exhibiting great application potential in uranium alloy materials. The corrosion resistance performance as well as the internal alloy phase structure of uranium–niobium alloy is closely related to aging processes. Microstructure and hydriding characteristics of the 400 °C/9 h + 500 °C/2 h aged uranium–13 at.% niobium alloys (U–13 at.%Nb) were investigated from the point of view of relationship between the microstructure and growth of the hydriding areas. The microstructure, morphology and composition of the alloy phases before and after the hydriding were well characterized by the laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Experimental results indicated that the hydrogen preferentially reacted with the Nb-depleted phase α-like-U to form monolithic β-UH 3 Nb x , and the alloy microstructure played an important role in hydride growth.