Grain boundary migration and Zener pinning in particle-containing copper crystals

Abstract

CuAl single crystals have been partially internally oxidised to produce a microstructure which contains a dispersion of small Al2O3 particles in part of a crystal, leaving the rest of the crystal single phase. After deformation and annealing, the single phase region recrystallizes readily, but in general the recrystallization front is halted at the single/two-phase interface. However, it is found that, at intermediate strains, grains with misorientations of ∼40° about axes close to 〈111〉 with respect to the deformed matrix, may penetrate the two-phase region. The results are interpreted in terms of an orientation dependence of the particle pinning pressure (Zener drag), and the implications of this on the grain size and texture of heat treatable alloys are discussed.