Microstructural evolution investigated with equal channel angular pressing

We explore the ability of existing models to capture microstructural evolution in complex deformation histories using a technique not yet applied to ductile deformation of rocks. We employ equal channel angular pressing (ECAP), in which a sample shaped as a cylinder or rectangular parallelepiped is forced through an angled extrusion channel. The angle in the channel imparts a net deformation on the sample that is effectively simple shear. However, for any parcel of sample, the shear strain rate is heterogeneous in time, resulting in a deformation path that involves initial annealing followed by a gradual increase in strain rate, a gradual decrease in strain rate, and a final stage of annealing. If samples can be recovered and reused, they may be passed through the channel again in a different orientation, imparting simple shear on a plane different to the previous shear plane. Our initial experiments focus on applying …