Evolution dependence of vanadium nitride nanoprecipitates on directionality of ion irradiation

The influence of the directionality of Fe2+ ion irradiation on the evolution of vanadium nitride platelet-shaped nanoprecipitates at 500 °C was investigated in a ferritic alloy using transmission electron microscopy. When the ion-irradiation direction was approximately aligned with the initial particle length, particles grew longer and sectioned into shorter lengths at higher doses, resulting in increased particle densities. As ion-irradiation direction deviated from particle-length direction, some particles sectioned lengthwise and then dissolved, resulting in decreased particle densities. Surviving particles were transformed into parallelograms with a different orientation relationship with the matrix. Nanoprecipitate evolution dependence on beam-nanoprecipitate orientation is a process that may be different from reactor irradiation.