氢对12Cr-ODS钢中强化相(Y_2O_3)辐照稳定性影响研究

通过离子束-电子束(H++e-)双束同时辐照,原位观察氧化物在辐照过程中的组织损伤变化,研究了(H++e-)双束辐照对乙二胺四乙酸(EDTA)络合溶胶-凝胶法制备的12Cr-ODS铁素体钢中氧化物(Y2O3)稳定性的影响。实验结果表明:电子辐照剂量达15 dpa后,再进行(H++e-)双束辐照15 dpa,在此条件下,Y2O3氧化物会发生尺寸减小或溶解,辐照诱发点缺陷和合金元素界面化学反应是导致氧化物不稳定性的重要原因。     

多束系统对12Cr-ODS钢辐照损伤协同效应的研究

室温下用不同种类的离子束对12Cr-ODS钢进行辐照。辐照前后12Cr-ODS钢的力学性能发生了明显变化,主要表现为辐照肿胀和辐照硬化,其中三束辐照下材料有最大的肿胀和最小的硬化。结合TEM照片对材料的辐照变化进行了分析。对材料进行拉曼光谱的测量,发现有碳析出现象,并且把碳峰的强度分布与辐照损伤分布进行了相互关联。本文为12Cr-ODS钢在实际反应堆中的应用积累了实验数据,明确了协同作用对核材料辐照损伤的影响。     

双束(H~+/e~-)同时辐照对12Cr-ODS钢氧化物稳定性影响

利用氢离子和电子双束(H~+/e~-)对用化学浸润法制备的新型12cr-ODS铁素体钢进行辐照,研究了辐照对12Cr-ODS钢氧化物稳定性的影响.对不同辐照剂量下原位观察辐照区内氧化物形貌的变化过程发现:辐照前和15 dpa辐照后,约10～20nm氧化物的尺寸并没有明显变化,而氧化物周围出现微小高密度空洞并没有影响氧化物的稳定性;当辐照温度升高至823 K时,大尺寸的氧化物Y_2O_3与基体的相界面变得不规则,但氧化物颗粒尺寸并不发生明显变化.实验结果表明:弥散强化相Y_2O_3尺寸稳定,无明显溶解现象.     

双束(He+/e-)辐照下氦对12Cr-ODS铁素体钢组织损伤影响研究

利用氦离子(He+)束和电子(e-)束双束同时辐照化学溶胶法制备的新型12Cr-ODS铁素体钢.实验结果表明,辐照初期,随着辐照剂量增加,点缺陷团(黑斑)在基体内形成,密度不断增大,尺寸长大缓慢,辐照剂量为0.8dpa时形成问隙型位错环.不同试验温度下,辐照均产生小尺寸高密度的空洞,随着辐照剂量增加,空洞尺寸长大缓慢,...     

双束强辐照对氧化物弥散强化铁素体型合金强化相稳定性影响

采用双束复合辐照装置,研究了He存在条件下,强辐照对长期时效后的ODS合金中强化相(Y2O3)的稳定性和辐照损伤特征的影响。实验结果表明:双束强辐照下,ODS合金中强化相不稳定,发生聚集长大并造成附近基体中Ti、Y浓度增高,导致空洞尺寸和空洞肿胀增加,并对这一结果从理论上进行解释。     

双束（H+/e-）辐照下氢对12Cr-ODS铁素体钢组织损伤影响研究

利用氢离子（H⁺）束和电子（e^-）束双束（H⁺/e^-）同时辐照用化学浸润法制备的新型12Cr-ODS铁素体钢,研究其辐照损伤效应及组织变化。实验结果表明：由于氧化物的钉扎,基体内保持低密度位错网络;辐照初期随辐照剂量的增加,缺陷团在位错线上及其周围形成,尺寸增加,密度不断增大,并形成间隙型位错环;不同温度下辐照均产生小尺寸高密度的空洞,随辐照剂量的增大,空洞长大速度降低,空洞密度缓慢减小;不同温度下,辐照剂量达15dpa时,空洞肿胀均小于0.15%。对辐照产生的点缺陷与氢相互作用进行理论分析,12Cr-ODS铁素体钢在623~823K经双束辐照后,表现出良好的抗辐照损伤性。     

He/H离子辐照损伤及其对ODS钢显微硬度的影响研究

为研究氧化物弥散强化铁素体钢(ODS钢)中的He/H离子协同辐照效应,本文开展了室温条件下ODS钢的He/H离子单一及复合辐照实验,并研究了辐照损伤对其显微硬度的影响。实验结果表明:He/H离子主要分布在损伤峰值附近;H离子辐照对ODS钢显微硬度的影响大于He离子;H离子的引入导致He离子低温解吸峰消失,而He离子的注量减半则使其热解吸起始温度升高;He、H离子与材料中缺陷相互作用不同是影响显微硬度及正电子寿命结果的主要因素。     

硅对低活化马氏体钢电子辐照行为的影响

利用超高压透射电子显微镜研究了两种成分的低活化马氏体钢(CLAM钢)的辐照损伤行为。结果表明：电子辐照能在未添加硅的CLAM钢中产生辐照空洞;在450℃下辐照至14dpa时,空洞数密度约为8.7×10²¹m^－3,辐照肿胀率约为0.26％;在450℃下的辐照肿胀率明显比500℃下的高;当损伤率为2×10^－3dpa/s时,添加合金元素硅能显著提高CLAM钢的抗辐照肿胀能力,未在添加硅的CLAM钢中实验观察到辐照空洞的形成。在450℃下进行辐照时,添加硅的CLAM钢出现明显的辐照共格析出现象。     

辐照损伤对反应堆压力容器钢电磁性能的影响

介绍了国内外在反应堆压力容器钢辐照脆化过程中电、磁性能的变化规律研究方面所开展工作,并讨论了目前所取得的研究成果与存在的不足。最后通过探索指出了反应堆压力容器钢在服役时力学性能、电性能与磁性能之间的潜在关联,以此为基础形成无损评估技术,可为反应堆压力容器钢辐照监督提供一个新的思路,并可作为现阶段传统辐照监督破坏性试验评价方法的一个重要补充。     

注氘低活化马氏体钢在电子辐照下的缺陷行为

低活化铁素体/马氏体(RAFM)钢被视为国际热核聚变反应堆以及聚变反应堆的第1壁候选结构材料之一,很多国家均在研究不同的RAFM钢,中国低活化马氏体(CLAM)钢的研究亦正在进行。核聚变会产生氢、氦、氘及氚,这些气体元素与辐照缺陷结合在一起,对材料的辐照性能会产生较大影响。本文对注氘后不同温度下的辐照后微观结构进行研究。试验利用日本北海道大学的JEOL-1300高压电子显微镜研究注氘CLAM钢从室温到873K在1250keV电子辐照下的微观结构变化。研究结果表明,在电子辐照下,注氘产生的缺陷团会出现消失和长大两种现象,意味着间隙型与空位型位错环在注氘过程中同时产生。并研究了注氘产生的空洞。     

Synthesis and Characterization of Oxide Dispersion Strengthened Ferritic Steel via a Sol-Gel Route

Nanocrystalline oxide dispersion strengthened （ODS） ferritic steel powders with nominal composition of Fe-14Cr-3W-0.3Ti-0.4Y2O3 are synthesized using sol-gel method and hy- drogen reduction. At low reduction temperature the impurity phase of CrO is detected. At higher reduction temperature the impurity phase is Cr2O3 which eventually disappears with increasing reduction time. A pure ODS ferritic steel phase is obtained after reducing the sol-gel resultant products at 1200℃ for 3 h. The HRTEM and EDS mapping indicate that the Y2O3 particles with a size of about 15 nm are homogenously dispersed in the alloy matrix. The bulk ODS ferritic steel samples prepared from such powders exhibit good mechanical performance with an ultimate tensile stress of 960 MPa.     

Characterization of High Temperature Creep Properties in Recrystallized 12Cr-ODS Ferritic Steel Claddings

The high temperature strengthening mechanism of previously manufactured 12Cr-ODS ferritic steel claddings was clarified. In the recrystallized 12Cr-2W-0.3Ti-0.24Y₂O₃-ODS ferritic steel cladding, αY₂TiO₅ type complex oxide formation was responsible for the drastic reduction of oxide particle size and the resulting shortened distance between particles, which led to superior internal creep rupture strength at 973 K because of the high resistance to gliding dislocation. Internal creep deformation was considered to be controlled by the grain boundary sliding associated with grain morphology: the near Σ11, Σ and Σ19 coincidence boundaries with a (110) common axis.     

Preliminary Tube Manufacturing of Oxide Dispersion Strengthened Ferritic Steels with Recrystallized Structure

The effect of cold wall temperature on separative performances for ¹⁴N¹⁵N-¹⁴N₂ separation was studied with the thermal diffusion column of an effective height of 950 mm, a hot wire of 0.15 mm in radius and a cold wall of 5.0 mm in radius. The column was maintained at a constant pressure 0.1 MPa with feed flow rate of 10 cm³.min^-1 (at 0.1 MPa and 298.15 K). The temperature of the cold wall was changed from 223 to 283 K by 20 K keeping at the same temperature difference 235 K between the hot and cold walls. The total separation factor became larger as the cold wall temperature decreased, but had almost the same value at 223 K and 243 K. The experimentally obtained separation factors were compared with the results of the numerical analyses of a convection-diffusion equation. The solutions of numerical analyses with thermal diffusion factor incorporated with inelastic effect gave a good reproduction of dependence of separation factors on cut and cold wall temperature rather than those without inelastic effect. The discrepancy between experimental and analytical results, however, became larger as the cold wall temperature decreased.     

Effects of Grain Morphology and Texture on High Temperature Deformation in Oxide Dispersion Strengthened Ferritic Steels

Oxide Dispersion Strengthened (ODs) ferritic steel is the promising candidate alloy for long-life core materials of fast reactor. A series of experiments, such as tensile tests, creep rupture tests, texture measurements and microstructure observations, are performed for the fabricated sheets of ODs ferritic steel with simulating type of morphology and also for the cladding tube in order to clarify the origin of the peculiar strength anisotropy of the cladding tube: degraded creep rupture strength in hoop direction. From these experiments, effects of grain morphology and texture on deformation of ODs ferritic steels are evaluated.

The sheets and the cladding tube have strong texture of {001}?110? and {111}?110?, respectively. In longitudinal and transverse directions of the sheets, strength level is significantly different from each other, but crystallographic orientation is almost equivalent. From that finding, it is considered that strength anisotropy of the cladding tubes is not attributed to the texture. From the results of micro structure analysis, it is concluded that origin of the degraded creep rupture strength in transverse hoop direction of the cladding tube comes from the grain boundary sliding at the large tilt angles.     

先进反应堆用ODS F/M钢的强韧性匹配研究进展

氧化物弥散强化（ODS）铁素体/马氏体（F/M）钢具有极高的缺陷阱密度,加之体心立方结构基体,使其具有优异的抗辐照性能,被确定为包括聚变堆和第4代裂变堆在内的先进核能系统关键部件候选材料,成为核材料领域的研究热点。有利于ODS钢抗辐照性能的显微组织特点同时也赋予了ODS钢优异的室温和高温强度。但和其他高强度材料类似,ODS钢也存在强度高,而塑韧性不足的矛盾,不利于复杂部件的加工,因此,实现ODS F/M钢的高强高韧成为面向工程应用的ODS F/M钢研究的一大热点和难点。目前,针对ODS F/M钢强韧化的研究还较少,已有的相关研究也不够系统和深入,本文主要对抗辐照ODS F/M钢的显微组织结构要求及其强韧化研究现状进行总结和分析,为先进反应堆用抗辐照ODS F/M钢的强韧化设计提供思路和参考。