为了通过实验阐明金属玻璃(MG)Gd65Co35 在温度循环(低温复壮)复壮作用下结构和动力学非均匀性的变化,研究人员开展了高能 X 射线衍射(HEXRD)、反常 X 射线散射(AXS)和非弹性 X 射线散射(IXS)实验。通过在液氮温度与室温之间重复进行 40 次温度变化,HEXRD 观察到即使在第一近邻范围内也出现了微小但清晰的结构变化。AXS 获得的部分结构信息表明,在以 Gd 原子为中心的第一和第二近邻壳层中,Gd 和 Co 原子发生了轻微移动。温度循环使 Gd 原子在纳米尺度上的浓度非均匀性显著增加,而其他非均匀性则可忽略不计。IXS 检测到微观弹性质发生明显变化:纵声学激发的宽度展宽约 20%,表明该热处理增加了这种金属玻璃的弹性非均匀性。这些静态和动态结果从实验上明确阐明了低温复壮效应的特征。
英文摘要:
To experimentally clarify the changes in structural and dynamic heterogeneities in a metallic glass (MG), Gd65Co35, by rejuvenation with a temperature cycling (cryogenic rejuvenation), high-energy x-ray diffraction (HEXRD), anomalous x-ray scattering (AXS), and inelastic x-ray scattering (IXS) experiments were carried out. By a repeated temperature change between liquid N2 and room temperatures 40 times, tiny but clear structural changes are observed by HEXRD even in the first neighboring range. Partial structural information obtained by AXS reveals that slight movements of the Gd and Co atoms occur in the first- and second-neighboring shells around the central Gd atom. The concentration inhomogeneity in the nm size drastically increases for the Gd atoms by the temperature cycling, while the other heterogeneities are negligible. A distinct change was detected in a microscopic elastic property by IXS: The width of longitudinal acoustic excitation broadens by about 20%, indicating an increase of the elastic heterogeneity of this MG by the thermal treatments. These static and dynamic results explicitly clarify the features of the cryogenic rejuvenation effect experimentally.
Strong rejuvenation in a chiral-glass superconductor
本文用squid磁强计研究了Bi $_2$ Sr $_2$ CaCu $_2$ O $_x$超导体($x$ = 8.18)的玻璃态顺磁迈斯纳相,并采用了以前研究自旋玻璃的“直流记忆”实验。在特定的冷却方案之后,在重新加热时记录零场冷却和热回复磁化的温度依赖性,其中在恒定温度下执行单次或多次停止。在暂停期间平衡的“自旋”状态在重新加热时恢复。所观察到的记忆和再生效应与海森堡自旋玻璃中观察到的相似。
Negative Strain-Rate Sensitivity in Metallic Glasses Driven by Rejuvenation-Relaxation Competition: Kinetic Monte Carlo Simulations and a Minimal Effective Model
Faculty of Mechanical Engineering, Kanazawa University(金泽大学机械工程学院);Department of Mechanical Science and Bioengineering, The University of Osaka(大阪大学机械科学生物工程系);Department of Earth and Space Science, The University of Osaka(大阪大学地球空间科学系)
Universal Dynamic Scaling for Sub-Yield Aging and Over-Yield Rejuvenation in A Cyclically Driven Metallic Glass
School of Materials Science and Engineering, Anhui University of Technology(安徽工业大学材料科学与工程学院);Advanced Interdisciplinary Science Research Center (AiRCenter), Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences(中国科学院宁波材料技术与工程研究所先进交叉科学研究院);State Key Laboratory of High Performance Roll Materials and Composite Forming, School of Material Science and Engineering, Hebei University of Technology(河北工业大学材料科学与工程学院高性能轧辊材料及复合成形省部共建国家重点实验室培育基地)
Unlocking Cryogenic Energy Storage by Constructing Dipole Glass with Unit-cell-level Polar Disorder
Harbin Institute of Technology, Shenzhen(哈尔滨工业大学(深圳));City University of Hong Kong(香港城市大学);Westlake University(西湖大学);Institute of Physics, Chinese Academy of Sciences(中国科学院物理研究所);The Hong Kong Polytechnic University(香港理工大学);University of Science and Technology Beijing(北京科技大学);University of Chinese Academy of Sciences(中国科学院大学);Institute of Metal Research, Chinese Academy of Sciences(中国科学院金属研究所);Indian Institute of Science(印度科学学院);Korea Advanced Institute of Science and Technology(韩国科学技术院);Peking University(北京大学);Xi’an Jiaotong University(西安交通大学)
NOMATEN Centre of Excellence, National Center for Nuclear Research(国家核研究中心 NOMATEN 卓越中心);Center for Complexity and Biosystems, Department of Physics "Aldo Pontremoli", University of Milan(米兰大学物理学院复杂性与生物系统中心);Saarland University, Chair of Metallic Materials(萨尔兰大学金属材料讲席);Glass and Time , IMFUFA, Department of Science and Environment, Roskilde University(罗斯基勒大学科学与环境学院 IMFUFA 玻璃与时间);Department of Materials Science, Montanuniversität Leoben(莱奥本矿业大学材料科学系);Erich Schmid Institute of Materials Science, Austrian Academy of Sciences(奥地利科学院埃里希·施密德材料科学研究所);Department of Materials Science and Engineering, Johns Hopkins University(约翰斯·霍普金斯大学材料科学与工程系);Department of Mechanical Engineering, Johns Hopkins University(约翰斯·霍普金斯大学机械工程系);Department of Physics and Astronomy, Johns Hopkins University(约翰斯·霍普金斯大学物理与天文学系);Hopkins Extreme Materials Institute, Johns Hopkins University(约翰斯·霍普金斯大学霍普金斯极端材料研究所);Technical University of Berlin, Chair of Metallic Materials(柏林工业大学金属材料讲席)
从零场冷却磁化强度随温度和时间的变化关系出发,研究了三维Ising自旋玻璃- Fe $_{0.55}$ Mn $_{0.45}$ TiO $_3$ -的非平衡动力学.结果表明,平衡自旋组态的混沌,再生和记忆功能,是非常相似的原型RKKY自旋玻璃Ag(Mn)的相应研究中观察到的。样品在零磁场中快速冷却,并在重新加热时记录磁化强度。当在冷却期间在恒定温度$T_s$下停止时,系统在该温度下向其平衡态演变。停止期间建立的平衡状态在进一步冷却时冻结,并在重新加热时恢复。在$T_s$下的老化记忆不受在较低温度下第二次停止$T'_s$的影响。反过来,在$T_s$的第一个平衡没有影响的松弛在$T'_s$,如预期的液滴模型中的域生长在一个混乱的景观。
Predicting Complex Relaxation Processes in Metallic Glass
弛豫过程显著影响玻璃材料的性质。然而,了解它们的具体起源是困难的,更具有挑战性的是从理论上预测它们。在这项研究中,使用微秒级分子动力学模拟和精确的多体相互作用势,我们预测Al $_{\text{90}}$ Sm $_{\text{10}}$金属玻璃将具有复杂的弛豫行为:除了主($α$)松弛,玻璃(i)显示出明显的次级(ii)表现出伴随$β$弛豫的反常弛豫过程($α_2$)。这两种预测都得到了实验的验证。计算模拟揭示了弛豫过程的微观起源:虽然明显的$β$弛豫归因于丰富的弦状合作原子重排,异常的$α_2$过程被发现与退耦的Al与较慢的Sm原子的快速运动。模拟和实验的结合代表了什么可能成为玻璃物理学的预测程序和不可分割的一步的第一印象。