66,516 research outputs found
Atomic mechanism of internal friction in a model metallic glass
No full textInternal friction (IF) describes the ability of materials to damp out mechanical oscillations. It is a crucial engineering parameter and also conveys unique microscopic information about structural defects, transport phenomena, and phase transformations in solids. While IF predominately results from lattice defects in crystalline materials, the origin of IF remains unclear in disordered materials, like metallic glasses. In this paper, we study the atomic rearrangements that govern IF in a model metallic glass, via numerical simulations of dynamical mechanical spectroscopy together with structural analysis. We identify cooperative and avalanchelike thermal-driven excitations as an underlying mechanism and demonstrate a linearlike relation between the concentrations of these excitations and the values of IF. Structurally, these excitations can be hindered, and thus suppress IF, by slow atoms that usually associate with full icosahedral symmetry. Our results also provide practical guides in tuning IF in metallic glasses from atomistic perspectives.Deutsche Forschungsgemeinschaft (DFG) [FOR 1394
Hai bin yu fu.
No full text什之譯.本電子書乃根據《香港版權條例(第528章)》而複製, 並只可在大學圖書館系統內的獨立電子書系統上使用.Shizhi yi.Ben dian zi shu nai gen ju "Xianggang ban quan tiao li (Di 528 zhang)" er fu zhi, bing zhi ke zai da xue tu shu guan xi tong nei de du li dian zi shu xi tong shang shi yong
Structural rearrangements governing Johari-Goldstein relaxations in metallic glasses
No full textAtomistic simulations reveal that secondary relaxations in metallic glasses originate from string-like atomic motions.</jats:p
Correlation between Viscoelastic Moduli and Atomic Rearrangements in Metallic Glasses
No full textDynamical moduli, such as storage and loss moduli, characterize the viscoelasticity of materials (i.e., time-dependent elasticity) and convey important information about the relaxation processes of glasses and supercooled liquids. A fundamental question is what ultimately determines them in glassy materials. Here, for several model metallic glasses, we demonstrate that both the storage and loss moduli are uniquely determined by the most probable atomic nonaffine displacements, regardless of temperature or frequency. Moreover, the fast-moving atoms (which contribute to dynamical heterogeneity) do not contribute explicitly to the moduli. Our findings provide a physical basis for the origin of viscoelasticity in metallic glasses
Fr. Paul Yu Bin
No full textFr. Paul Yu Bin (于 斌) wearing a surplice and a stole.https://digitalcommons.whitworth.edu/album06/1141/thumbnail.jp
Bishop Paul Yu Bin
No full textBishop Paul Yu Bin with locals at Guilin. Guilin, China. B/W Photo.https://digitalcommons.whitworth.edu/cmh_notable_persons/1023/thumbnail.jp
Archbishop Yu Bin
No full textArchbishop Yu Bin on the occasion of his consecration to Archbishop. He was made a Cardinal in 1969. Nanjing, China. B/W Photo.https://digitalcommons.whitworth.edu/cmh_notable_persons/1005/thumbnail.jp
Sur les traces de Yu Bin
No full textSortie du film Sur Les Traces de Yu Bin de Jean-Christophe Yu à Bruxelles et à Liège Voici un documentaire à ne manquer sous aucun prétexte. "Sur la piste de Yu Bin" est une émouvante et remarquable exploration de la mémoire familiale et individuelle de son réalisateur Jean-Christophe Yu. Il y fait l’éclatante démonstration de l’universalité des destins humains lorsqu’ils sont racontés avec talent, poésie et sincérité. Dans ce long métrage documentaire, constitué pour l’essentiel d’images d’..
The beta relaxation in metallic glasses: an overview
No full textMetallic glasses, combining metallic bonding and disordered atomic structures, are at the cutting edge of metallic materials research. Recent advances in this field have revealed that many key questions in glassy physics are inherently connected to one important relaxation mode: the so-called secondary (beta) relaxation. Here, in metallic glasses, we review the features of beta relaxations and their relations to other processes and properties. Special emphasis is put on their current roles and future promise in understanding the glass transition phenomenon, mechanical properties and mechanisms of plastic deformation, diffusion, physical aging, as well as the stability and crystallization of metallic glasses
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