Recovery and ordering in cold-rolled boron-doped Ni76Al24

The annealing behavior of a highly ordered intermetallic compound, i.e., boron-doped Ni76Al24, was studied for three degrees of cold rolling. The prerecrystallization phenomenon was found to consist of two mechanisms: recovery and restoration of order. The order parameter restored with annealing varied with the degree of cold rolling. Recovery was detected by a decrease in hardness and strain (measured by a half-maxima width). Ordering took place continuously in the case of 25 pct rolled material; however, the 85 pct deformed material showed that ordering was restored in two stages; the first stage was faster than the second. The 45 pct one showed some unusual features in ordering behavior. The hardness and strain parameter measurements also confirmed the presence of various stages before the onset of recrystallization. Those were verified by transmission electron microscopy and quantified in terms of the degree of order, which, in turn, depended on the degree of rolling.