The diffusive behavior of B atoms in Ni3Al(0.98at%B) alloy has been investigated by positron annihilation technique after the alloy was homogenized at high temperature and followed by quenching in water
cooling in air and cooling in furnace respectively. It was shown that the amount of B atoms segregating to grain boundaries for the alloy cooled in furnace was the most
whereas the least for that quenched in water
and that a little of boride was formed at the grain boundaries in the former case.In order to make the alloy with moderate segregation of B atoms to grain boundaries and without boride formed there
the alloy was recommended to be cooled in air after being homogenized at high temperature.