Analysis of ostwald ripening in ni-rich ni-ti alloys by diffusion couples

Abstract

The coarsening kinetics of γ' precipitates in Ni-rich Ni-Ti alloys are studied using a Ni-11·5 wt% Ti and pure Ni diffusion couple. The formed concentration gradient allowed to study the aging process at 1023 K (750 °C) in Ni-rich Ni-Ti alloys with Ti content from 8·62 to 11·15 wt% Ti. In general, during the coarsening of γ' precipitates, the experimental coarsening kinetics do not fit well to the LSW or TIDC theoretical models and anomalous behaviour of coarsening rate constant (kr) associated with γ' volumefraction is confirmed at high values.