Radiation Embrittlement Understanding for PLIM Activities at EC-JRC-IE

Radiation embrittlement and aging mechanisms for NPP reactor pressure vessels and vessel internals have been studied within NPP Plant Life Management activities for the evaluation, prediction, and monitoring of the critical components' service life. The main achievements of the SAFELIFE project, integrating various networks on PLIM issues, are given. Results of neutron embrittlement of model alloys are presented, and surveillance and research data on WWER reactor pressure vessel and other steels are analyzed. Projects for the development of destructive and non-destructive testing of irradiated materials are outlined.     

空冷系统低温结垢问题的快速处理及运行效果

分析空冷系统低温结垢形成原因 ,从全系统经济运行的角度 ,对药剂治理、静电治理和降低空冷塔局部浓缩倍数达到治理低温结垢效果进行比较 ,提出低温结垢的处理方法。     

Hydrogen Embrittlement Processes and AL／AL2O3 Hydrogen Resistance Coatings of NdFeB Magnets

After analyzing the phenomena and processes of hydrogen embrittlement of NdFeB permanent magnets, RF magnetron sputtering was used to fabricate A1 thin films and then oxidized to form the Al/Al2O3 composite films on the magnets as the hydrogen resistance coatings. SEM and EDS were used to examine the morphology and composition respectively. Hy-drogen resistance performance was tested by exposing the magnets in 10 MPa hydrogen gas at room temperature. The results show that the magnets with 8μm Al/Al2O3 coatings can withstand hydrogen of 10 MPa for 65 min without being embrittledinto powd er. The samples with and without hydrogen resistance coatings have almost the same magnetic properties.     

吸尘器叶轮上片铝材加工工艺研究

详细地研究了吸尘器叶轮上片用5052合金板材的冷加工工艺。结果表明，通过采取对铸锭进行均匀化处婵和合理控制最终冷轧变形量以及适当提高回火温度的方法，可以使材料力学性能与深冲性能获得良好的匹配，表面质量稳定，完全满足用户的使用要求。     

二次整体回火处理混流式水轮机转轮叶片裂纹

本文介绍了浙江省湖南镇水电站水轮机转轮叶片裂纹情况及其处理方法，并分析了叶片发生裂纹的原因。同时还介绍了针对在裂纹处理过程中可能产生的变形问题所做的试验。     

拉伸速率对Ni40 Ti50 Fe10合金环境氢脆的影响

研究了不同应变速率对Ni40Ti50Fe10合金环境氢脆的影响,并用扫描电子显微镜观察了拉伸断口的形貌.研究结果表明:Ni40Ti50Fe10合金在真空中的拉伸行为与应变速率无关,断口形貌主要是韧窝塑性断口.Ni40Ti50Fe10合金在空气中的塑性随着应变速率的降低而减小,断口形貌也从韧窝塑性断口转变为韧窝塑性断口和解理脆性断口的混合断口.Ni40Ti50Fe10合金在氢气中低应变速率拉伸时表现出明显的脆性,断口形貌主要为解理脆性断口.在高应变速率下(2×10-1s-1),Ni40Ti50Fe10合金在真空、空气和氢气中的塑性相近,说明在该应变速率下可以有效地抑制环境氢脆.Ni40Ti50Fe10合金的屈服强度不受应变速率和环境的影响.     

SCK-CEN Contribution to the IAEA Round Robin Exercise on WWER-440 RPV Weld Material: Irradiation,Annealing, and Re-Embrittlement

Mechanical properties of WWER-440 RPV weld joints have been studied with account of different states of the material: baseline (unirradiated), irradiated up to the average fast neutron fluence of 6.5 10¹⁹ n/cm², irradiated and eventually annealed, re-irradiated with the accumulated fast neutron fluence of 1.3 10²⁰ n/cm², Tensile, impact fracture, and fracture toughness tests were performed for each state of the material with the use of Charpy specimens (standard, reconstituted, and pre-cracked).     

Simulation of hydride-induced steady-state crack growth in metals – Part II: general near tip field

Hydride-induced steady-state crack propagation in metals is investigated under conditions of constant temperature, plane strain, small-scale yielding and small-scale hydride precipitation, by taking into account the coupling of the operating physical processes. It is shown that the near-tip field depends on a normalized stress intensity factor, which incorporates both effects of the applied stress intensity factor and the crack velocity. According to Part I of the present study, when the normalized stress intensity factor tends to zero, the crack-tip field near the threshold stress intensity factor is produced, which is characterized by a constant hydrostatic stress in the hydride precipitation zone. As the value of the normalized stress intensity factor increases, the evolution of the near-tip field for crack propagation from stage-I to stage-II regime is produced: the actual size of the hydride precipitation zone decreases, the hydrostatic stress increases, deviating from the level of the plateau, and the near-tip field tends to that of a hydrogen-free metal. The near-tip field depends strongly on hydrogen concentration, far from the crack tip. The stage-II crack growth velocity is predicted and the experimentally observed effect of metal yield stress and temperature on crack velocity is confirmed.The present study is part of the project on Hydrogen Embrittlement and Fracture in Hydride Forming Metals, financed by the Foundation for Knowledge and Competence Development and performed in cooperation with Studsvik Nuclear AB and Barsebäck Kraft AB.     

组织细化对中碳Cr-Mo钢力学性能的影响

通过循环热处理和改变奥氏体化温度两种方法获得不同的原奥氏体晶粒尺寸,研究了不同晶粒尺寸对高温回火中碳Cr-Mo钢力学性能的影响.结果表明,当奥氏体化温度低于1 050℃时,实验钢的强度随奥氏体化温度的升高而提高.在相同的奥氏体化温度下,强度随着晶粒的细化而上升.在整个研究范围内,随着晶粒的细化,实验钢的韧性有一定的提高,塑性略有下降.晶粒细化显著提高了钢的低温冲击韧性.     

热处理工艺对高钼高钒高速钢轧辊组织和性能的影响

研究了淬火温度、冷却方式、回火温度和回火次数对高钼、高钒高速钢轧辊组织和性能的影响。结果表明，油冷条件下，淬火温度低于1050℃，随着温度升高，硬度升高，超过1100℃，硬度反而降低。盐浴冷却（盐冷）和空冷条件下，淬火温度对硬度影响结果相似，但获得最高硬度的淬火温度高于油冷时的淬火温度。回火温度低于350℃，高速钢硬度变化不明显，超过475℃，随回火温度升高，硬度升高，并在525oC达到最高值，继续提高回火温度，硬度降低。二次回火后硬度变化不大，三次回火后，硬度反而降低。空冷高速钢轧辊，淬透性差，油冷高速钢轧辊易出现裂纹，盐冷高速钢轧辊，具有优良的淬透性，不易出现裂纹，辊面硬度高，硬度均匀性好，耐磨性好。