Strength α‐Quartz: New Results From High Pressure In Situ X‐Ray Diffraction Experiments

Abstract We present a suite of 13 uniaxial deformation experiments on fine grained polycrystalline α‐quartz conducted in a D‐DIA apparatus monitored with in situ synchrotron x‐rays. Experimental temperatures range from 25°C to 1199°C with pressures between 1.4 and 3.2 GPa, and strain rates between 3.4 × 10 −6 s −1 and 1.8 × 10 −5 s −1 . Powder diffraction data from the (), (), (), () and () lattice planes were forward modeled using elastic plastic self‐consistent (EPSC) simulations to derive differential stresses. We consistently observe temperature dependent inelastic behavior at low strain which we simulate using an isotropic deformation system in the EPSC model. Our mechanical data is broadly consistent with mechanical data from previous deformation studies conducted in the Griggs solid‐medium deformation apparatus and can be described by a combination of a Guyot and Dorn rate equation for plasticity limited by lattice resistance below 800°C and with a dislocation creep flow low above 800°C.