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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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Lattice strain and texture analysis of superhard Mo 0.9 W 1.1 BC and ReWC 0.8 via diamond anvil cell deformation
Mo 0.9 W 1.1 BC and ReWC 0.8 compositions have recently been identified to have exceptional hardness and incompressibility. In this work, these compositions are analyzed via in situ radial X-ray diffraction experiments to comparatively assess lattice strain and texture development. Traditionally, Earth scientists have employed these experiments to enhance understanding of dynamic activity within the deep Earth. However, nonhydrostatic compression experiments provide insight into materials with exceptional mechanical properties, as they help elucidate correlations between structural, elastic, and mechanical properties. Here, analysis of differential strain ( t / G ) and lattice preferred orientation in Mo 0.9 W 1.1 BC suggests that dislocation glide occurs along the (010) plane in orthorhombic Mo 0.9 W 1.1 BC. The (200) and (002) planes support the highest differential strain, while planes which bisect two or three axes, such as the (110) or (191), exhibit relatively lower differential strain. In ReWC 0.8 , which crystallizes in a cubic NaCl-type structure, planar density is correlated to orientation-dependent lattice strain as the low-density (311) plane elastically supports more differential strain than the denser (111), (200), and (220) planes. Furthermore, results indicate that ReWC 0.8 likely supports a higher differential stress t than Mo 0.9 W 1.1 BC and, based on a lack of texture development, bulk plastic yielding is not observed in ReWC 0.8 upon compression to ∼60 GPa.
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- Award ID(s):
- 1654687
- PAR ID:
- 10161386
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 7
- Issue:
- 41
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 24012 to 24018
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C9TA06431A
