Effect of Temperature and Hydride on Fatigue Crack Growth Behaviour of Zr-Sn-Nb Alloy Welded Seam

The fatigue crack growth rate tests of base material and welded seam of hydrogenated and non-hydrogenated Zr-Sn-Nb alloy were carried out at room temperature and 360 ℃ by using small-size three-point bending specimens. The effects of temperature and hydride on the fatigue crack growth behavior of thin welded sheets were studied. The results show that after corrosion hydrogen absorption, horizontally distributed flaky hydrides are precipitated in both the base material and the welded seam zone. Compared with the base material, the hydride precipitated in the welded zone is much denser. At the same temperature, the fatigue crack growth resistance of non-hydrogenated base material is better than that of non-hydrogenated welded seam. After corrosion hydrogen absorption, the fatigue resistance of base material at the same temperature is also better than that of welded seam. At room temperature, the fatigue crack growth resistance of base material and welded seam after corrosion hydrogen absorption significantly reduce compared to that before hydrogen absorption. At 360 ℃, the hydrides in the base material and welded seam are partially dissolved, so that its fatigue crack growth resistance improves to a certain extent.