skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Probing Microplasticity in Small-Scale FCC Crystals via Dynamic Mechanical Analysis

Authors:
; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1351701
Grant/Contract Number:
SC0014109
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 118; Journal Issue: 15; Related Information: CHORUS Timestamp: 2017-04-14 22:16:07; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Ni, Xiaoyue, Papanikolaou, Stefanos, Vajente, Gabriele, Adhikari, Rana X., and Greer, Julia R.. Probing Microplasticity in Small-Scale FCC Crystals via Dynamic Mechanical Analysis. United States: N. p., 2017. Web. doi:10.1103/PhysRevLett.118.155501.
Ni, Xiaoyue, Papanikolaou, Stefanos, Vajente, Gabriele, Adhikari, Rana X., & Greer, Julia R.. Probing Microplasticity in Small-Scale FCC Crystals via Dynamic Mechanical Analysis. United States. doi:10.1103/PhysRevLett.118.155501.
Ni, Xiaoyue, Papanikolaou, Stefanos, Vajente, Gabriele, Adhikari, Rana X., and Greer, Julia R.. Fri . "Probing Microplasticity in Small-Scale FCC Crystals via Dynamic Mechanical Analysis". United States. doi:10.1103/PhysRevLett.118.155501.
@article{osti_1351701,
title = {Probing Microplasticity in Small-Scale FCC Crystals via Dynamic Mechanical Analysis},
author = {Ni, Xiaoyue and Papanikolaou, Stefanos and Vajente, Gabriele and Adhikari, Rana X. and Greer, Julia R.},
abstractNote = {},
doi = {10.1103/PhysRevLett.118.155501},
journal = {Physical Review Letters},
number = 15,
volume = 118,
place = {United States},
year = {Fri Apr 14 00:00:00 EDT 2017},
month = {Fri Apr 14 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.118.155501

Citation Metrics:
Cited by: 3works
Citation information provided by
Web of Science

Save / Share:
  • In situ scanning electron microscope (SEM) experiments, where small-scale mechanical tests are conducted on micro- and nanosized specimens, allow direct visualization of elastic and plastic responses over the entirety of the volume being deformed. This enables precise spatial and temporal correlation of slip events contributing to the plastic flow evidenced in a stress–strain curve. A new pin-loading methodology has been employed, in situ within the SEM, to conduct microtensile tests on thin polycrystalline metal foils. This approach can be tailored to a specific foil whose particular grain size may range from microns to tens of microns. Manufacture of the specializedmore » pin grip was accomplished via silicon photolithography-based processing followed by subsequent focused ion beam finishing. Microtensile specimen preparation was achieved by combining a stencil mask methodology employing broad ion beam sputtering along with focused ion beam milling in the study of several metallic foil materials. Finite-element analyses were performed to characterize the stress and strain distributions in the pin grip and micro-specimen under load. Furthermore, under appropriately conceived test conditions, uniaxial stress–strain responses measured within these foils by pin-load microtensile testing exhibit properties consistent with larger scale tests.« less
  • The ease of processing hybrid organic–inorganic perovskite (HOIPs) films, belonging to a material class with composition ABX 3, from solution and at mild temperatures promises their use in deformable technologies, including flexible photovoltaic devices, sensors, and displays. To successfully apply these materials in deformable devices, knowledge of their mechanical response to dynamic strain is necessary. The authors elucidate the time- and rate-dependent mechanical properties of HOIPs and an inorganic perovskite (IP) single crystal by measuring nanoindentation creep and stress relaxation. The observation of pop-in events and slip bands on the surface of the indented crystals demonstrate dislocation-mediated plastic deformation. Themore » magnitudes of creep and relaxation of both HOIPs and IPs are similar, negating prior hypothesis that the presence of organic A-site cations alters the mechanical response of these materials. Moreover, these samples exhibit a pronounced increase in creep, and stress relaxation as a function of indentation rate whose magnitudes reflect differences in the rates of nucleation and propagation of dislocations within the crystal structures of HOIPs and IP. In conclusion, this contribution provides understanding that is critical for designing perovskite devices capable of withstanding mechanical deformations.« less
  • An investigation of the activation parameters for plastic deformation in the microstrain region was performed. Vanadium single crystals with (491) axial orientations were tested in compression by strain rate cycling at various intervals over the strain range of 1 x 10/sup -5/ to 2 x 10/sup -3/ at a strain sensitivity of 5 x 10/sup -7/. Tests were conducted between 125 and 300 K on a series of crystals containing interstitial solute concentrations in the range 486 at. ppM to 1649 at. ppM oxygen plus nitrogen content. The results indicate that in the microstrain region more than one dislocation processmore » is occurring. The results are consistent with the theory that edge and nonscrew dislocations are the mobile species in the microstrain region at low temperatures. As deformation proceeds, the mobile densities of the edge and nonscrew segments decrease and the transition to macroflow is associated with the onset of screw dislocation motion. The data indicate that in the microstrain region edge and nonscrew dislocation mobility is strongly affected by solute interactions. In the macrostrain regions, however, flow rate is apparently controlled by screw dislocation--lattice interactions. 13 figures, 1 table.« less
  • The silyl-functionalized/protected derivatives of the tetrakis(perfluoroaryl)borate anions, B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and B(C{sub 6}F{sub 4}TIPS){sub 4}{sup -} (TBS = tert-butyldimethylsilyl and TIPS = triisopropylsilyl) have been synthesized, and a series of stable, highly reactive Zr and Th ion-paired methyl and hydride catalysts have been isolated using these anions. In contrast, the analogous B(C{sub 6}F{sub 5}){sub 4}{sup -}-based zirconocene methyl complexes are not stable at room temperature; however, B(C{sub 6}F{sub 5}){sub 4}{sup -}-based zirconocene hydride complexes can be isolated. The relative coordinative ability of the series of fluoroarylborates with respect to metallocene cations has been evaluated on the basis ofmore » spectroscopic and reactivity data. The polymerization activity of the zirconocene catalysts reaches a maximum when B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and B(C{sub 6}F{sub 4}TIPS){sub 4}{sup -} are counteranions, and the polymerization activity of the Zr constrained geometry catalyst reaches a maximum in aromatic solvents due to arene coordination when B(C{sub 6}F{sub 5}){sub 4}{sup -} is the counteranion. 37 refs., 5 figs., 7 tabs.« less