Microstructural Characterization of Excel Zirconium Alloy

Excel zirconium alloy (Zr-3.5Sn-0.8Mo-0.8Nb) was manufactured in the 80's within the research programs for the development of high strength materials for CANDU (CANada Deuterium Uranium) pressure tubes. Excel test results showed a better dimensional stability, a higher creep resistance andits hydrides are less susceptible to reorientation during service, compared with the current material in use, Zr-2.5Nb. These factors extend the useful life of the tubes and make Excel a good option for the production of pressure tubes. The aim of the present work is to characterize the microstructure of this alloy analyzing specimens with different contents of hydrogen. The phases were studied using optical microscopy, SEM, TEM and X-ray diffraction. The quantitative chemical analysis was performed using EDS technique.