温度及氢化物对Zr-Sn-Nb合金焊缝疲劳裂纹扩展行为的影响研究

采用小尺寸三点弯曲试样完成了渗氢和未渗氢Zr-Sn-Nb合金母材和焊缝在室温和360 ℃下的疲劳裂纹扩展速率试验，研究了温度和氢化物对焊接薄板的疲劳裂纹扩展行为的影响。结果表明，腐蚀吸氢后，在母材和焊缝区均析出了呈水平向分布的片状氢化物。相比母材区，焊缝区析出的氢化物更为致密。在相同温度下，未渗氢母材的抗疲劳裂纹扩展性能均优于未渗氢焊缝。腐蚀吸氢后，母材在相同温度下的抗疲劳裂纹扩展性能也优于焊缝。在室温下，腐蚀吸氢后的母材和焊缝的抗疲劳裂纹扩展性能相比吸氢前明显下降。360 ℃下，渗氢母材和焊缝中的氢化物部分溶解，使得其抗疲劳裂纹扩展性能得到一定程度提升。

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.