【摘要】 采用紧凑拉伸试样(CT),在恒定载荷、不同氢含量、不同温度条件下,测量了CANDU堆和RBMK堆Zr-2.5Nb压力管材料氢致延迟开裂速率。用金相显微镜和扫描电镜观察断口及氢化物形貌,并测量临界应力场强度因子及开裂速率,对材料的微结构及氢化物分布进行分析。结果表明,氢致延迟断裂(DHC)生长呈阶梯状。与CANDU压力管比较,RBMK压力管的DHC开裂速率将近低一个数量级。其原因是RBMK压力管的屈服强度比CANDU压力管低得多。更多还原

【Abstract】 Using Compact tension specimen (CT), delayed hydride cracking (DHC) tests were imple-mented to determine cracking velocities in CANDU Zr-2.5Nb pressure tube and RBMK standard pressure tube under constant loading and different temperature and different hydrogen contents. The DHC fracture surface and hydride distribution were observed by SEM. The results of the tests show that crack growth dis-plays stairs shape, probably due to hydrogen accumulating and diffusing at crack tip. The highest DHC veloc-ity is inherent in the CANDU pressure tubes. The DHC velocity in the RBMK pressure tubes is lower by an order and even more. This difference in the DHC velocities owes to different yield strength of CANDU Zr-2.5Nb pressure tube and RBMK standard pressure tube.更多还原