CaSiO3 perovskite was synthesized in a diamond cell and its lattice strain anisotropy was measured under non-hydrostatic compression to conditions corresponding to 61 GPa. Experiments were performed using energy dispersive synchrotron X-ray diffraction in a radial geometry. The equation of state of CaSiO3 perovskite obtained from lattice strains measured at different angles from the loading direction can describe the range of compression curves previously reported under quasi-hydrostatic and non-hydrostatic conditions. The ratio of the differential stress to the shear modulus increases from 0.016(5) to 0.039(4) for CaSiO3 perovskite over pressures from 19 to 61 GPa. In combination with a theoretical prediction for the shear modulus, room-temperature yield strengths are 3-11 GPa for CaSiO3 perovskite over this pressure range. Under the assumption that the effect of the tetragonal distortion is minimal, the elastic constants for CaSiO3 perovskite were recovered. Single-crystal elastic constants of CaSiO3 perovskite are in good agreement with theoretical predictions for the cubic phase. In particular, the elastic anisotropy, S, decreases from 0.0020(7) to 0.0004(2) GPa-1 over the 19-61 GPa pressure range. Comparison with theoretical elasticity data provides evidence for possible strength anisotropy.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Physics and Astronomy (miscellaneous)
- Space and Planetary Science
- Equation of state
- X-ray diffraction
- Yield strength