In this work, uniaxial creep tests under 300, 350 and 380 MPa were performed to study the synergy of stress and corrosion in a 12Cr ferritic/martensitic (F/M) steel exposed to static liquid lead-bismuth eutectic (LBE) at 550 & DEG;C. The results showed that LBE had a strong degradation effect especially under low-oxygen condition, leading to drastic acceleration of creep deformation as compared to that in air. Although oxide scales, such as magnetite, Fe-Cr spinel and chromium oxide, could slow down crack initiation and propagation, this effect is load and oxygen concentration dependent. The overall creep behavior is governed by multiple competing mechanisms.

Ferrite/martensite steel is an important material candidate for nuclear reactor claddings owing to its excellent mechanical properties and radiation resistance. In particular, the hot deformation behavior of 12Cr‐ferritic/martensitic (12Cr‐F/M) steel is crucial for the fabrication of cladding tubes, and experiments performed in a wide temperature range could reveal the possible thermal deformation behavior of 12Cr‐F/M steel during tube fabrication. Herein, hot compression experiments of 12Cr‐F/M steel are conducted with strain rates and deformation temperatures ranging from 0.005 to 5 s −1 and 750 to 1200 °C, respectively. According to the thermal deformation flow and thermal expansion curves of the alloy, the Arrhenius‐type constitutive equations before and after the phase transformation of 12Cr‐F/M steel are established, taking 950 °C as the critical point. The results show that for a strain rate of 0.5 s −1 , the cooling intensity increases gradually with the deformation temperature. The ferrite transforms into a mixed structure of ferrite and pearlite and finally transforms into martensite. At 950 °C, the degree of austenitization of the alloy increases with the strain rate, and the texture changes from cubic to brass.

本文介绍了推进N36皓合金科技成果转化的原因、主要做法与经验积累.在积极强化能源战略要求、响应科技成果转化号召、助推单位实现高质量发展的背景下,中国核动力研究设计院以策划、评估、实施、检查作为"四大基本程序",做好组织、人力、激励、团队建设"四大保障",实施了锆合金科技成果转化,成果转化收益增长明显,助推单位实现自身高质量发展,显著提升了自身技术水平与实力,树立了核行业成果转化典范,切实落实了创新驱动战略.积累了成果转化的重要经验与做法,更加注重坚持战略导向、强化核心需求牵引、量化过程权属、加强制度建设.

铁素体马氏体(F/M)钢是铅冷快堆堆芯的主要候选材料之一,提高S i含量可提高其抗腐蚀性能,但影响其微观结构和力学性能.为研发兼顾力学性能和抗腐蚀性能的高Si含量F/M钢,本文对Si含量(质量分数为0.34％、0.61％、0.80％、0.98％ 和1.20％)对9％Cr F/M钢微观结构和力学性能的影响进行了研究.结果显示,室温下通过正火(1050℃,0.5 h,空冷)+回火(760℃,1.5 h,空冷)热处理制备的F/M钢均为全马氏体组织.钢的屈服强度和抗拉强度均随Si含量的增加而增加.Si含量对钢的组织及冲击性能的影响可分为两个阶段,当F/M钢中Si含量为0.34％ ～0.80％ 时,其组织、冲击性能变化很小;Si含量为0.98％ ～1.20％ 时,F/M钢中的第二相尺寸、数量增加,沿马氏体板条界面析出少量的Laves相,F/M钢的冲击韧性降低.本研究9％Cr F/M钢中Si元素的最优添加量应低于0.8％,使钢在保持较高强度的同时兼具良好的韧性.

铁素体马氏体(F/M)钢是铅冷快堆堆芯的主要候选材料之一,提高F/M钢中的Si含量可提高其抗腐蚀性能,但会促进Laves相的析出从而影响其塑韧性.针对5种Si含量(0.34～1.20 mass％)的9％Cr F/M钢,开展了 600℃下热老化不同时间的试验,研究了 Si含量对其Laves相析出行为和冲击性能的影响.结果表明:热老化250 h后,5种Si含量的F/M钢均在原奥氏体晶界和马氏体板条界面上析出了不规则颗粒状为主的Laves相;随着热老化时间的增加,Laves相面积分数先增加后保持稳定,而平均直径逐渐增加.相同的热老化时间下,Laves相的密度和面积分数随Si含量的增加逐渐增加,但随着Si含量的增加,Si含量的影响呈现逐步减弱的趋势,当Si含量达到0.98 mass％后,进一步增加Si含量不会显著影响Laves相的析出行为.Si含量对Laves相的平均直径、粗化速度和化学成分的影响不显著,Laves相在600℃下的粗化速度约为8.5 nm/h1/3.热老化250 h后,不同Si含量的F/M钢冲击性能均显著退化;相同热老化时间下,F/M钢的冲击性能随Si含量的增加有下降的趋势,Laves相的析出是冲击性能退化的主要原因.

The structure of the oxide scales formed on three ferritic/martensitic (F/M) steels, including HT9, T91 and CLA16 exposed to oxygen-saturated lead-bismuth eutectic (LBE) at 400°C for 500 h has been studied. The results show that the oxide scales in the three steels have a similar triple-layered structure. The outer layer is a nanosized/ultrafine magnetite containing massive Pb solid solution nanoparticles. An Fe-Cr spinel constitutes the intermediate layer without the Pb particles. The innermost layer is a Cr oxide (i.e., Cr2O3) that forms preferentially at the martensite lath boundaries. A refined oxidation mechanism is proposed with consideration of the Cr oxide formed at the oxidation front, as well as of an improved “Pb nano-channels” theory.

对锻造态铁素体/马氏体(F/M)钢进行了两种不同挤压比的挤压-不同道次冷轧实验,研究不同工艺对F/M钢管材微观组织及力学性能的影响.结果 表明,经热挤压、退火后,两条工艺路线制备的F/M钢管材均为马氏体组织,且细小的碳化物粒子在马氏体基体上均匀分布.在多道次轧制、退火过程中,大变形量的管材发生完全再结晶,微观组织是铁素体晶粒;而小变形量的管材发生部分再结晶,微观组织由铁素体和板条马氏体构成;在相同道次冷轧和退火后,发生了完全再结晶的管材强度较低塑性高,只发生部分再结晶的管材表现出高强度和低塑性.经过相同的正火和回火后,两条工艺路线制备的成品管中马氏体板条宽度为200～300nm,室温屈服强度为590～610 MPa,550℃时屈服强度为330～350MPa.

为在较低烧结温度下制备具有高锂离子电导率的Li6.5 La3Zr1.5 Ta0.5 O12电解质,采用固相法,将低熔点的硼酸锂(Li3 BO3)固态电解质按照一定比例与Li6.5 La3 Zr1.5 Ta0.5 O12电解质复合,制备了10组含有不同比例Li3 BO3添加量的Li3 BO3-Li6.5La3Zr1.5Ta0.5O12复合固态电解质(Li3BO3与Li6.5La3Zr1.5Ta0.5O12物质的量比值为0～0.9),相应烧结温度降低至800℃.同时为明确Li3 BO3对复合电解质致密化烧结的影响规律及作用机制,对10组复合电解质的组成、结构形貌及离子电导率性能进行横向比较.发现其锂离子电导率随Li3 BO3添加量的增加出现先升高后降低的趋势,其中Li3 BO3与电解质物质的量比值为0.7的样品室温锂离子电导率高于其他9组,约为4.5×10-5 S/cm,而未添加Li3BO3样品锂离子电导率仅为5.5×10-6 S/cm.通过扫描电子显微镜(scanning electron microscope,SEM)观察发现,Li3 BO3可促使Li6.5 La3 Zr1.5 Ta0.5 O12晶粒长大及致密化,因此通过与Li3 BO3复合可提高Li6.5 La3 Zr1.5 Ta0.5 O12电解质的性能.

利用高压釜腐蚀的锆合金板材样品,研究了锆合金氧化膜的横纵向开裂演变及腐蚀转折机理.分析发现,氧化膜中的纵向通道仅为转折发生的必要结构,氧化膜/金属界面横向缺陷带的萌生、扩展及连通是转折发生的主要控制过程,且界面金属凸起部位的微观应力聚集是氧化膜开裂的主要原因.根据研究结果提出了转折关联机制,可为新型锆合金开发提供指导.

锆合金是目前军用舰船核动力和商用压水堆燃料元件包壳唯一可选材料.国内尚无实现工程化应用的锆合金,长期依赖进口受制于人,是我国关键基础材料的短板之一,必须开展自主知识产权先进锆合金研发.中国核动力研究设计院在30年来锆合金研发积累的基础上,充分借鉴国际先进锆合金研发经验,历经10年的艰苦科研攻关,以军民结合为指引,成功实现了N36锆合金工程化.本文介绍了N36锆合金自主化的背景、总体思路、研产历程、相关成果.锆合金自主研产成功,使得我国获得了完整的自主知识产权,具有良好的技术经济性.这有利于保障军用核级锆合金包壳的稳定供应,有利于保证中国核电站的运行和发展以及军用核动力材料供应安全,具有典型的军民结合示范意义.

Second phase particles (SPPs) in N36 zirconium alloy claddings and bars was studied by SEM and TEM equipped with EDS.The result showed that SPPs in the claddings and the bars nearly have the same average diameter,but have different morphology and distribution.Zr(Nb,Fe)2 Laves phase and a few of β-Nb phase precipitates were detected both in N36 alloy claddings and bars by diffraction and EDS analysis,but Laves.phase in the bars had lower Nb content and smaller crystal lattice than that in the claddings.This study also illuminated that Nb content in α-Zr matrix for the cladding approaches to the solubility limit which appears equal to 0.3 wt～0.4 wt％,which is much lower than the usually assumed value of 0.6 wt％.

Zr-Sn-Nb-Fe alloy is one of the high performance zirconium alloys used as the fuel cladding materials for high burnup fuel elements. The corrosion behavior of zirconium alloys were affected by the alloying element, the microstructure and fabricating process. To better understand the effect of Nb on the corrosion behavior of Zr-Sn-Nb-Fe alloy, Zr-xNb-0.4Sn-0.3Fe (x=0 similar to 1, mass fraction, %) sheets were prepared by thermo-mechanical processing and tested in static autoclave in 360 degrees C, 18.6 MPa pure water, 360 degrees C, 18.6 MPa, 0.01 mol/L LiOH aqueous solution, and 400 degrees C, 10.3 MPa superheat steam. The characteristics of the microstructure were analyzed by TEM and SEM. It was shown that the corrosion weight gain of specimens was increased when x increaseed from 0 to 1 in pure water and steam. However, it was found that the corrosion weight gain reduced in LiOH aqueous solution as Nb content was increased. The microstructural characteristic indicated the addition of Nb has the effect of refining recrystallization grain of Zr-xNb-0.4Sn-0.3Fe alloy. The mean size of the precipitates in alloy were almost the same even though the Nb was considerably changed, but the area fraction of precipitates and mass ratio of Nb/Fe in precipitates of alloy were increased with the Nb content increasing when all the samples heat treated in the same condition. The ZrFe or ZrNbFe precipitate of including small amounts of Nb was mainly formed when x was 0.2 or less, and the ZrNbFe precipitate was mainly found when the content of Nb was higher. With the increasing of corrosion rate, there are more cracks in the fracture surface of the oxide films and the size of "Cauliflower-like" structure grows bigger. It was concluded that the contents of Nb in ZrNbFe precipitates will be responsible for the difference of corrosion resistance for Zr-xNb-0.4Sn-0.3Fe alloy.

High temperature tensile creep behavior of N36 zirconium alloy cladding tubes in the temperature range from 593 K to 723 K and the stress range from 60 MPa to 160 MPa was investigated. The results show that there are three distinct rate-controlled creep mechanisms for N36 zirconium alloy cladding tubes. In the temperature range from 593 K to 673 K the stress exponent n is similar to 3 and creep activation Q approximate to 150 kJ.mol(-1) is found in the low applied stress region, which means the dominant process is viscous-glide-controlled. But in the high applied stress region the stress exponent n is 5-6 and the creep activation Q approximate to 170 kJ.mol(-1) is found, which obeys the typical five power law creep mechanism controlled by the climb of edge dislocations. At 723 K and with high applied stress the power law breakdown appears and the exact mechanism is not clear by now. In the test condition N36 zirconium alloy cladding tubes exhibit a type of creep behavior similar to that noted in class-I(A) alloys, which is very different from zircaloy.

随着国内科技水平的不断发展，我国对科研项目的管理要求也在逐渐的提高，特别是从事科学研究的单位，而科研过程中的质量管理是科研项目管理中的重中之重。随着国家的质量管理体系在不断创新时，各部门的质量管理体系也要与时俱进。本文阐述了科研项目管理的相关理论，对加强科研质量管理的重要意义进行了分析，并提出对策。