Positron annihilation in B-doped and undoped single and polycrystalline Ni3Al alloys

Coincidence Doppler broadening spectra measurements on B-doped and undoped single and polycrystalline Ni3Al alloys exhibit characteristic differences. The probability of the positron-3d electron annihilations decreases with the increase of B concentration in single crystals of Ni3Al alloys, while it increases with B concentration in polycrystals of Ni3Al alloys, as long as the concentration of B is less than its solubility limit. The behavior of positrons and B atoms in single and polycrystals of Ni3Al alloys has been discussed.