γ′ Precipitation and Growth Kinetics in Mechanically Alloyed Ni–Al

الملخص EN

The precipitation and growth kinetics of γ′ precipitates, which are strengthening factors in Ni-base oxide dispersion strengthened (ODS) superalloys, were investigated.

The cuboidal-type γ′ precipitates are formed in conventional arc-melted Ni–Al alloys, whereas spherical-type precipitates are formed in the mechanically alloyed (MAed) specimens.

The morphology is controlled by a lattice misfit between the γ′ precipitates and the matrix at the aging temperature of 800°C.

The growth kinetics of the γ′ precipitates can be followed by Ostwald ripening.

The Arrhenius plot yielded a lower activation energy for the solute atom diffusion in MAed specimens, which is attributed to their high dislocation density and nanosized grains.