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1. Texture Development and Stress–Strain Partitioning in Periclase + Halite Aggregates

   https://doi.org/10.3390/min9110679  

   Lin, F.; Giannetta, M.; Jugle, M.; Couper, S.; Dunleavy, B.; Miyagi, L. (November 2019, Minerals)

   Multiphase materials are widely applied in engineering due to desirable mechanical properties and are of interest to geoscience as rocks are multiphase. High-pressure mechanical behavior is important for understanding the deep Earth where rocks deform at extreme pressure and temperature. In order to systematically study the underlying physics of multiphase deformation at high pressure, we perform diamond anvil cell deformation experiments on MgO + NaCl aggregates with varying phase proportions. Lattice strain and texture evolution are recorded using in-situ synchrotron x-ray diffraction and are modeled using two-phase elasto-viscoplastic self-consistent (EVPSC) simulations to deduce stress, strain, and deformation mechanisms in individual phases and the aggregate. Texture development of MgO and NaCl are affected by phase proportions. In NaCl, a (100) compression texture is observed when small amounts of MgO are present. In contrast, when deformed as a single phase or when large amounts of MgO are present, NaCl develops a (110) texture. Stress and strain evolution in MgO and NaCl also show different trends with varying phase proportions. Based on the results from this study, we construct a general scheme of stress evolution as a function of phase proportion for individual phases and the aggregate. 

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2. Low‐Temperature Plasticity in Olivine: Grain Size, Strain Hardening, and the Strength of the Lithosphere

   https://doi.org/10.1029/2018JB016736  

   Hansen, Lars N.; Kumamoto, Kathryn M.; Thom, Christopher A.; Wallis, David; Durham, William B.; Goldsby, David L.; Breithaupt, Thomas; Meyers, Cameron D.; Kohlstedt, David L. (June 2019, Journal of Geophysical Research: Solid Earth)

   Abstract Plastic deformation of olivine at relatively low temperatures (i.e., low‐temperature plasticity) likely controls the strength of the lithospheric mantle in a variety of geodynamic contexts. Unfortunately, laboratory estimates of the strength of olivine deforming by low‐temperature plasticity vary considerably from study to study, limiting confidence in extrapolation to geological conditions. Here we present the results of deformation experiments on olivine single crystals and aggregates conducted in a deformation‐DIA at confining pressures of 5 to 9 GPa and temperatures of 298 to 1473 K. These results demonstrate that, under conditions in which low‐temperature plasticity is the dominant deformation mechanism, fine‐grained samples are stronger at yield than coarse‐grained samples, and the yield stress decreases with increasing temperature. All samples exhibited significant strain hardening until an approximately constant flow stress was reached. The magnitude of the increase in stress from the yield stress to the flow stress was independent of grain size and temperature. Cyclical loading experiments revealed a Bauschinger effect, wherein the initial yield strength is higher than the yield strength during subsequent cycles. Both strain hardening and the Bauschinger effect are interpreted to result from the development of back stresses associated with long‐range dislocation interactions. We calibrated a constitutive model based on these observations, and extrapolation of the model to geological conditions predicts that the strength of the lithosphere at yield is low compared to previous experimental predictions but increases significantly with increasing strain. Our results resolve apparent discrepancies in recent observational estimates of the strength of the oceanic lithosphere. 

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3. Severe Strain‐Induced Olivine‐Ringwoodite Transformation at Room Temperature: Key to Enigmas of Deep‐Focus Earthquake

   https://doi.org/10.1029/2024GL111281  

   Lin, F.; Levitas, V_I; Yesudhas, S.; Dhar, A.; Smith, J. (March 2025, Geophysical Research Letters)

   Abstract Deep‐focus earthquakes at 350–660 km are presumably caused by olivine‐spinel phase transformation (PT). This cannot, however, explain the observed high seismic strain rate, which requires PT to complete within seconds, while metastable olivine does not transform for over a million years. Recent theory quantitatively describes how severe plastic deformations (SPD) can solve this dilemma but lacking experimental proof. Here, we introduce dynamic rotational diamond anvil cell with rough diamond anvils to impose SPD on San Carlos olivine. While olivine never transformed to spinel at room temperature, we obtained reversible olivine‐ringwoodite PT under SPD at 15–28 GPa within tens of seconds. The PT pressure reduces with increasing dislocation density, microstrain, plastic strain, and decreasing crystallite size. Results demonstrate a new strain‐induced PT mechanism compared to a pressure/temperature‐induced one. Combined with SPD during olivine subduction, this mechanism can accelerate olivine‐ringwoodite PT from millions of years to timescales relevant to earthquakes. 

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4. The effect of strain path changes on texture evolution and deformation behavior of Ti6Al4V subjected to accumulative angular drawing

   https://doi.org/10.1016/j.msea.2019.138168  

   Kawałko, J.; Muszka, K.; Graca, P.; Kwiecień, M.; Szymula, M.; Marciszko, M.; Bała, P.; Madej, Ł.; Beyerlein, I.J. (September 2019, Materials Science and Engineering: A)

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5. Viscous anisotropy of textured olivine aggregates: 2. Micromechanical model: VISCOUS ANISOTROPY OF OLIVINE AGGREGATES

   https://doi.org/10.1002/2016JB013240  

   Hansen, Lars N.; Conrad, Clinton P.; Boneh, Yuval; Skemer, Philip; Warren, Jessica M.; Kohlstedt, David L. (October 2016, Journal of Geophysical Research: Solid Earth)