The T91 grade and similar 9Cr tempered-martensitic steels (also known as ferritic-martensitic) are leading candidate structural alloys for fast fission nuclear and fusion power reactors. At low temperatures (300 to 400 $^\circ$C) neutron irradiation hardens and embrittles these steels, therefore it is important to investigate the origin of this mode of life limiting property degradation. T91 steel specimens were separately neutron irradiated to 2.14 dpa at 327 $^\circ$C and 8.82 dpa at 377 $^\circ$C in the Idaho National Laboratory Advanced Test Reactor. Atom probe tomography was used to investigate the segregation driven formation of Mn-Ni-Si-rich (MNSPs) and Cu-rich (CRP) co-precipitates. The precipitates increase in size and, slightly, in volume fraction at the higher irradiation temperature and dose, while their corresponding compositions were very similar, falling near the Si(Mn,Ni) phase field in the Mn-Ni-Si projection of the Fe-based quaternary phase diagram. While the structure of the precipitates has not been characterized, this composition range is distinctly different than that of the typically cited G-phase. The precipitates are composed of CRP with MNSP appendages. Such features are often observed in neutron irradiated reactor pressure vessel (RPV) steels. However, the Si, Ni, Mn, P and Cu solutes concentrations are lower in the T91 than in typical RPV steels. Thus, in T91 precipitation primarily takes place in solute segregated regions of line and loop dislocations. These results are consistent with the model for radiation induced segregation driven precipitation of MNSPs proposed by Ke et al. Cr-rich alpha prime ($α$') phase formation was not observed.
Investigating the difference in mechanical stability of retained austenite in bainitic and martensitic high-carbon bearing steels using in situ neutron diffraction and crystal plasticity modeling
The Timken Company（铁姆肯公司）；Chemical and Engineering Materials Division, Spallation Neutron Source, Oak Ridge National Laboratory（橡树岭国家实验室散裂中子源化学与材料工程部）
Physics-informed neural network for predicting fatigue life of unirradiated and irradiated austenitic and ferritic/martensitic steels under reactor-relevant conditions
Extreme Environments Materials Group (EEMG), Department of Materials Engineering, Indian Institute of Science (IISc)（极端环境材料组（EEMG）、材料工程系、印度科学研究院（IISc））；Department of Materials, University of Oxford（材料系、牛津大学）；Robert Bosch Centre for Cyberphysical Systems, Indian Institute of Science (IISc)（罗伯特·博世网络物理系统中心、印度科学研究院（IISc））
Peculiar metastable structural state in carbon steel
本文研究了碳钢冷却相变动力学与预退火温度T $_{an}$的关系。结果表明，T $_{an}$ > A $_3$（i. e.高于铁素体开始的温度）以90 - 100 K/s的速率加热，导致基本上取决于T $_{an}$的结构状态;在750 $^0$ C < T $_{an}$ < 830 $^0$ C the transformation is of perlite type whereas at T $_{an}$ >830 $^0$ C时，马氏体结构出现。我们的研究结果表明，在一定的温度范围内形成一个特殊的结构状态附近和以上的两相区的边界，其特征在于基本上纳米级的碳分布，晶格畸变和磁短程有序的异质性。
Corrosion Evolution of T91 Steel in Static Lead-Bismuth Eutectic Under an Oxidising Environment
University of Oxford（牛津大学）；Max-Planck-Institute for Sustainable Materials（马克斯·普朗克可持续材料研究所）；Massachusetts Institute of Technology（麻省理工学院）；Australia's Nuclear Science and Technology Organisation（澳大利亚核科学与技术组织）
Design of a V-Ti-Ni alloy with superelastic nano-precipitates
应力诱发的马氏体相变使亚稳合金能够表现出增强的应变硬化能力，从而改善可成形性和韧性。然而，正如从相变诱发塑性（TRIP）钢中所熟知的，由于其固有的脆性，所得的马氏体可以限制延展性和疲劳寿命。在这项工作中，我们探索了一种合金设计策略，利用应力诱导马氏体相变，但不保留马氏体相。这种策略是基于超弹性纳米析出物的引入，其在初始应力诱导的正向转变后表现出反向转变。为此，利用从头算模拟和热力学计算，我们设计并制备了V45 Ti 30 Ni 25（at%）合金。在该合金中，TiNi作为纳米沉淀物均匀分布在韧性富V基心立方（bcc）β基质内，以及作为较大的基质相存在。我们使用各种扫描电子显微镜（SEM）和透射电子显微镜（TEM）的方法，其特征在于所产生的合金的微观结构。通过拉伸试验证明了合金的体力学性能，并且通过原位TEM微柱压缩实验、原位高能衍射同步加速器循环拉伸试验、压痕实验和差示扫描量热法实验证实了TiNi形貌中的可逆转变。观察到的转变途径和变量的影响相稳定性进行了严格的讨论
