Fatigue notch sensitivity of ultrafine-grained copper

Fatigue notch sensitivity of ultrafine-grained (UFG) copper of purity 99.9% produced by equal channel angular pressing was determined on cylindrical specimens with circumferential notches of different radii and compared with the notch sensitivity of conventional copper. Notch sensitivity of UFG copper is higher than that of its conventional counterpart. Electron back scattering diffraction technique showed that the UFG copper of purity 99.9% is not prone to grain coarsening during cycling. The grain structure within plastic zone around the cracks was found to differ substantially from that outside the plastic zone: the grains were markedly elongated, but their size was preserved.