Dependence of shear-induced mixing on length scale

The critical strain for mixing was determined as a function of precipitate size in two-phase Cu₉₀Ag₁₀ alloys using high-pressure torsion experiments. X-ray diffraction, Z-contrast transmission electron microscopy and atom probe tomography were employed to characterize the mixing behavior. For precipitates ranging from 16 to 131 nm in radius, the critical strain increased linearly with the initial precipitate size, with the proportionality constant at ≈5.2 nm^-1. These results are in agreement with model predictions based on random dislocation glide.