A study on the influence of impurities on the recovery and recrystallisation behaviour of cold rolled Ni above room temperature by means of positron annihilation

The recovery and recrystallisation behaviour of cold rolled Ni of different purity such as Ni doped with Sb, Ti and B between room temperature and 550°C was studied by measurement of the peak counting rate of 2γ-angular correlation during annealing with constant heating rate. The results indicate a strong dependence of the annealing behaviour on type and concentration of impurity atoms. For Ni of purity 99.8% and especially for NiSb the peak counting rate shows a large increment in the temperature region 200–400°C which is explained to be caused by the formation of vacancy clusters.