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| Titel |
Micro-scale strain mapping technique: a tool to quantify strain partitioning during creep deformation |
| VerfasserIn |
Alejandra Quintanilla-Terminel, Mark Zimmerman, Brian Evans, David Kohlstedt |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250130279
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| Publikation (Nr.) |
 EGU/EGU2016-10513.pdf |
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| Zusammenfassung |
| Several deformation mechanisms interact to accommodate plastic deformation. Quantifying
the contribution of each to the total strain is necessary for establishing a better link between
observed microstructures and mechanical data, as well as to allow more confident
extrapolation from laboratory to natural conditions.
In this contribution, we present the experimental and computational technique involved in
micro-scale strain mapping (MSSM). The MSSM technique relies on analyzing the relative
displacement of initially regularly spaced markers after deformation. We present several
microfabrication techniques that permit us to pattern various rocks with micrometric and
nanometric metal markers, as well as the challenges faced in working at high temperatures
and pressures. A Hough transform algorithm was used to detect the markers and automate as
much as possible the strain analysis. The von Mises strain is calculated for a set of n-points
and their relative displacements, which allow us to map the strain at different length
scales.
We applied the MSSM technique to study strain partitioning during deformation creep of
Carrara marble and San Carlos olivine at a confining pressure, Pc, of 300 MPa and
homologous temperatures of 0.3 to 0.6.
We measured the local strain and strain heterogeneity produced during creep deformation
of split cylinders of Carrara marble under conventional triaxial loading to inelastic strains of
11 to 36% at a strain rate of 3x10−5s−1, Pc = 300 MPa and 400o < T <700oC. We conclude
that the evolution of deformation structures in marble takes place over a substantial interval in
strain and that the duration of this interval depends on strain rate, temperature, and
pressure.
Our first results on strain mapping of olivine deformed at T = 1150oC and Pc = 300 MPa
demonstrate promise for characterizing intragranular strain and better defining the
contribution of grain boundary sliding to the total strain. |
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