A. To reach Higher pressures The
maximum pressure range so far explored is limited. For a DDIA, deformation
experiments have been performed only to ~10 GPa (to ~1600 K), and
for a RDA to ~18 GPa (at ~1800 K). In order to investigate the whole
mantle rheology including the lower mantle by laboratory experiments,
we need to extend the pressure range to ~25-30 GPa (and to temperature
of ~2000 K) (conditions at ~700-900 km in Earth’s mantle).
See details....
B. Sample assembly design In addition to the
need for improved anvil design, we will explore various modifications
of sample assembly designs. Design of a sample assembly including
the gasket is critical to achieve (homogenous) high pressure and
temperature. See details ....
C. Higher resolution in stress measurement We
have set a goal of 10 MPa for the precision of the stress measurements.
See details...
D. Control of grain size & Control of chemical environment
See details...
E. Inversion of x-ray diffraction data for macroscopic
stress estimate The development of x-ray diffraction technique
has allowed us to explore the details of polycrystal deformation
as summarized before. These studies provided, for the first time,
a means of inferring the nature of stress distribution in a polycrystalline
(and a multi-phase) material. However, these studies have also highlighted
a need for a better understanding of stress-strain distribution
in a deforming material in order to obtain a macroscopic stress
from the x-ray diffraction of individual diffraction peaks.See
details...
F. Automation and real-time creep software See
details...
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