Fracture resistance of Zr–Nb alloys under low-cycle fatigue tests

•Low-cycle fatigue tests of Zr–Nb alloys using DMA have been carried out.•The characteristics of low-cycle fatigue of the Zr–Nb alloy at 25/350°C were determined.•Increasing test temperature up to 350°C leads to a decrease of fatigue life.•The test temperature doesn’t have an effect on the character of fatigue curves. Comparative low-cycle fatigue tests of small-scale specimens cut from the cladding tubes of E110, E125, E110opt zirconium alloys at temperatures of 25 and 350°C using a dynamic mechanical analyzer have been carried out. It is shown that the limited cycles fatigue stress for all alloys is 50% less at temperature of 350°C comparing to 25°C. Besides it has been revealed that the limited cycles fatigue stress increases with increasing the strength of zirconium alloy.