LARGE-STRAIN DEFORMATION OF NI3AL+B .2. MICROSTRUCTURE AND TEXTURE EVOLUTION DURING RECRYSTALLIZATION

The microstructure evolution and texture development of the intermetallic compound Ni76Al24, doped with minor additions of boron, was investigated during annealing subsequent to cold-rolling. Upon annealing of cold-rolled specimens, a hardness increase prior to recrystallization was observed. This is attributed to a relaxation process of the dislocation cores during annealing. Recrystallization proceeded with very different kinetics locally and a very small recrystallized grain size was obtained. From grain growth kinetics, the activation energy for grain boundary motion was found to be close to the activation energy for self-diffusion of Ni in Ni3Al. The recrystallization texture was almost random. However, three texture components could be invariably recognized ({013}[100], {012}[021] and {112}[294]). They are related by special orientation relationships to the brass rolling orientation. A high frequency of annealing twins occurred in the recrystallized microstructure. The misorientation distribution function (MODF) shows a preference of certain low SIGMA boundaries, namely small-angle boundaries (SIGMA1) and twins (SIGMA3).