CHANNELING SIMULATION IN NI3AL

Measurements using ion channeling and Rutherford backscattering have indicated that Hf and Ta dopants in ordered Ni//3Al alloys are located predominately on the Ni sites. Because other experiments have indicated the dopants to be on the Al sites, computer simulations of the ion channeling and scattering processes have been performed to see whether some unusual factor could lead to erroneous conclusions when the standard methods to interpret channeling results are used. Consideration has been given to the effects of a higher average charge on the Al sites if high Z dopants are located there, to the effects of displacement amplitudes for the dopants that differ from those of the host atoms, and to the effects of mosaic spread in the crystal.