Changes in the microstructure of nanocrystalline Ni3Al were investigated by comparing a high-purity material with boron-doped (0.1 and 0.2wt%) compounds. The nanocrystalline microstructure was obtained by filing. X-ray diffraction was used to characterize the material properties after different thermal treatments. After filing the materials were completely disordered, with small crystallite size of about 10nm, similar in all materials. The influence of boron on the structural evolution was also investigated. For increasing annealing temperatures, the following phenomena took place successively: an increase in the LRO with crystallites; then a general improvement of the structure, with a decrease in the concentration of lattice defects. By comparison with pure Ni3Al, the presence of boron results in an increase of the temperature at which microstructure improvements take place. This latter should be related to the interactions of the boron atoms with point defects as well as dislocations.

Microstructure Evolution after Thermal Treatments of Nanocrystalline Ni3Al and Ni3Al+B Produced by Filing. Khitouni, M., Njah, N.: Physica Status Solidi C, 2004, 1[7], 1981-4