title: Direct evidence for grain boundary motion as the dominant restoration mechanism in the steady-state regime of extremely cold-rolled copper.
abstract: Ultra-fine-grained high-purity copper (99.99%) deformed by means of high-pressure torsion into the steady-state regime was subjected to additional rolling deformation. The microstructural changes as a function of the applied strain were analysed by means of orientation imaging microscopy. It was found that after a distinctive rolling strain a steady state with respect to microstructural features such as grain size, misorientation distribution and texture evolves again. A special spilt specimen technique was used to perform quasi in situ observations of the microstructure between additional strain increments. Profound insights into the local deformation and restoration processes within the steady-state regime were gained. The observations lead to the conclusion that grain boundary migration perpendicular to the rolling direction leads to the disappearance of certain grains, enabling the occurrence of a steady state.
authors.affiliation: Erich Schmid Institute of Materials Science, Jahnstrasse 12, 8700 Leoben, Austria.
authors.forename: O
authors.initials: O
authors.lastname: Renk
authors.affiliation: Department of Materials Physics, Montanuniversität Leoben, Jahnstrasse 12, 8700 Leoben, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Hohenwarter
authors.affiliation: Department of Materials Physics, Montanuniversität Leoben, Jahnstrasse 12, 8700 Leoben, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Wurster
authors.affiliation: Erich Schmid Institute of Materials Science, Jahnstrasse 12, 8700 Leoben, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Pippan
keywords: Cold-rolling; Copper; Grain boundary migration; Severe plastic deformation (SPD); Steady state