Defects formed under irradiation in the bulk act as additional pinning centers resulting in the well-known effect of radiation-induced hardening. On the other hand, there is a poorly understood but well-established effect of instant and reversible softening of metals subjected to various types of irradiation. This radiation-induced softening (RIS) effect should be taken into account both in the theory of radiation effects and in the engineering approach for technological applications. In the present paper, the RIS is investigated experimentally in polycrystalline technically pure iron (0.048%C) and in commercial ferritic steel. The effect of the electron beam on plastic deformation of bcc Fe is compared with that in fcc Al (99.5%). Electron energy ranged from 0.5 to 0.8 MeV. Reversible drop of the yield stress and radiation-induced reduction of the elongation to fracture are measured as functions of the electron current and specimen thickness. Rate theory of RIS is proposed, which takes into account the radiation-induced excitation of moving discrete breathers (DBs), recently proven to exist in bcc Fe, and their interaction with dislocations enhancing unpinning from structural defects. The behavior of the DBs is studied using classical MD simulations providing input for the modified rate theory, which eventually demonstrates a reasonable agreement with experimental data. The relevance of results to the in-reactor behavior of pressure vessel steels is discussed.
In situ $He^{+}$ irradiation of the double solid solution $(Ti_{0.5},Zr_{0.5})_{2}(Al_{0.5},Sn_{0.5})C$ MAX phase: Defect evolution in the 350-800 °C temperature range
Characterisation of Irradiation Damage in Fe3Cr and Fe5Cr: A Study on the Effects of Chromium Content and Temperature
University of Bristol(布里斯托大学);UK Atomic Energy Authority(英国原子能管理局);Ruđer Bošković Institute(鲁德·博什科维奇研究所);Advanced Photon Source, Argonne National Lab(阿贡国家实验室先进光子源);Indian Institute of Science(印度科学学院)
Irradiation of TiBe12 and CrBe12 with He+ ions and ex-situ transmission electron microscopy to investigate ion damage as a proxy for neutron irradiation damage in nuclear fusion
In-situ operation of amorphous circuits under heavy-ion irradiation
Shanxi University(山西大学);Liaoning Academy of Materials(辽宁省材料研究院);Institute of Metal Research, Chinese Academy of Sciences(中国科学院金属研究所);University of Science and Technology of China(中国科学技术大学);Harbin Institute of Technology(哈尔滨工业大学);Tianjin University(天津大学);Hebei University of Architecture(河北建筑工程学院);Peking University(北京大学);Jiangnan University(江南大学)
研究了电子辐照掺杂拓扑绝缘体Bi 2 Te 3的方法。为此,在室温下用2.5 MeV电子辐照p型Bi 2 Te 3单晶,并在高达14 T的磁场中进行原位和非原位电测量。通过辐照产生的缺陷充当电子供体,允许补偿材料的初始空穴型导电性以及导电性从p型到n型的转换。使用霍尔效应和Shubnikov-de Haas(SdH)振荡来研究载流子浓度的变化,这在照射前的p型样品中清楚地观察到,但在照射诱导的导电性转换为n型之后也是如此。沿三角轴的磁场观察到的SdH图案可以完全解释假设只有一个价带和导带的贡献,分别和塞曼分裂的轨道水平。
Plasticity in irradiated FeCrAl nanopillars investigated using discrete dislocation dynamics
在本文中,我们研究了塑性辐照FeCrAl纳米柱使用离散位错动力学模拟(DDD),与离子和中子辐照的商业FeCrAl合金C35 M的透射电子显微镜(TEM)原位拉伸试验的比较。辐照引起的缺陷,如a/2 111和100型环和成分波动的相分离的辐照FeCrAl合金的代表的影响,分别进行了研究,以及叠加在一起的模拟。我们探讨了缺陷对FeCrAl纳米柱的应力-应变行为,特别是屈服强度和硬化响应的影响。我们的模拟证实了被广泛接受的事实,即辐照合金表现出更高的屈服强度和硬化的应力应变响应相比,均匀的合金。然而,我们的DDD计算揭示了一个非典型的叠加硬化的贡献,由于组合物的不均匀性和辐射回路,其中硬化由于组合物的不均匀性抵消硬化由于辐射回路在小尺度。因此,我们观察到,在辐照合金的屈服强度,考虑到成分不均匀性和辐照回路的影响后,小于只有辐照回路的合金的屈服强度,并且对于单独的成分不均匀性的合金是大致相同的。我们确定这种相消干涉的叠加在我们的平行TEM原位拉伸试验未辐照,离子辐照,中子辐照C35 M FeCrAl合金以及。硬化贡献中的这种相消干涉与实验团体广泛使用的分散势垒硬化(DBH)模型形成对比,以模拟由于不同辐照引起的缺陷的硬化贡献。
A Deep Learning Based Automatic Defect Analysis Framework for In-situ TEM Ion Irradiations
University of Wisconsin-Madison(威斯康星大学麦迪逊分校);Oak Ridge National Laboratory(橡树岭国家实验室);University of Oxford(牛津大学);University of Michigan - Ann Arbor(密歇根大学安娜堡分校)
Rapid Primary Radiation Damage Resistance Assessment of Precipitation-Hardened Cu Alloys
Plasma Science and Fusion Center (PSFC)(等离子体科学与聚变中心);Department of Materials Science & Engineering(材料科学与工程系);Department of Nuclear Science & Engineering(核科学与工程系)
Progressive amorphization of GeSbTe phase-change material under electron beam irradiation
硫族化合物相变材料(PCM),特别是Ge-Sb-Te化合物中的快速和可逆的相变不仅是基本的兴趣,而且使基于PCM的随机存取存储器(PRAM)成为非易失性存储器和神经形态计算设备的主要候选者。为了使存储器单元稳定,结晶Ge-Sb-Te必须经历相变,首先到液态,然后到非晶态,对应于电阻的突变。在这项工作中,我们展示了一个渐进的非晶化过程中的GeSb 2 Te 4薄膜在电子束照射下的透射电子显微镜(TEM)。熔化被证明是完全不存在的原位TEM实验。渐进的非晶化过程非常类似于伴随电阻连续变化的累积结晶过程。我们的工作表明,如果位移力可以适当地实现,它应该是可以模拟对称的神经元动力学使用PCM。
Emerging hierarchical dislocation structures: Insights from scanning electron microscopy-electron backscatter diffraction in situ tensile testing and multifractal analysis
Synthesis and characterization of Ni0 NPs immobilized on acid activated montmorillonite (Ni°-Mont) as an efficient and reusable heterogeneous catalyst for one-pot synthesis of biscoumarins under microwave irradiation
Interstitial-mediated dislocation climb and the weakening of particle-reinforced alloys under irradiation
位错可以通过吸收(或发射)点缺陷(空位和自填隙原子(SIAs))爬出其滑移面。与保守的滑翔运动相反,爬升依赖于点缺陷的热扩散,因此在更长的时间尺度上运行,导致某些形式的蠕变。虽然平衡点缺陷浓度允许位错爬升以减轻非滑移应力,但点缺陷过饱和也会导致渗透力,即使在没有外部应力的情况下也会驱动位错运动。自填隙原子通常具有比空位高得多的形成能,因此它们对爬升的贡献通常被忽略。然而,在辐照条件下,这两种类型的缺陷以相等的数量非热地产生。在这封信中,我们使用简单的热力学参数来表明,在辐照材料中的贡献不可忽略,并且它们对位错引起的渗透力比空位引起的渗透力大许多个数量级。这就解释了为什么{ \it in situ}透射电子显微镜辐照观察到的棱柱形位错环更多的是间隙型而不是空位型。使用离散位错动力学模拟,我们调查的影响,位错障碍物的相互作用,并发现在许多数量级的脱钉时间减少。这对辐照下颗粒增强合金的强度具有重要影响。
Recrystallisation phenomena in an ultrafine-grained Al-Mg-Si alloy revealed by correlative in situ EBSD and TEM heating
Graz University of Technology(格拉茨工业大学);Graz Centre for Electron Microscopy (FELMI-ZFE)(格拉茨电子显微镜中心);Montanuniversität Leoben(莱奥本矿业大学);Institute of Aeronautics and Space, Brazilian Air Force(巴西空军航空与航天研究所)
CuCrZr heat-sink irradiation performance reveals new challenges for thermonuclear fusion reactors
Université Lorraine(洛林大学);Montanuniversität Leoben(莱奥本矿业大学);UKAEA (United Kingdom Atomic Energy Authority)(英国原子能管理局);SCK CEN(比利时核研究中心);Universidade de São Paulo Escola Politécnica(圣保罗大学理工学院)