Microscopic phase-field study on directional coarsening mechanism caused by interaction between precipitates in Ni-Al-V alloy
(State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China)
Abstract: A microscopic phase-field model was used to investigate a directional coarsening mechanism caused by the anisotropic growth of long period stacking and different effects of phases on precipitation in Ni-Al-V alloy. The results show that DO22 mainly coarsens along its short axis, which may press the neighboring L12, leading to the interaction among atoms. Diffusion channels of Al are formed in the direction where the mismatch between γ′ and γ reduces; the occupation probabilities are anisotropic in space; and direction coarsening of L12 occurs finally. With a rise of ageing temperature, phases appear later and DO22 is much later at a higher temperature, the average occupation probabilities of Al and V reduce, and Al changes more than V.
Key words: nickel-based alloys; microscopic phase-field simulation; directional coarsening; anisotropic growth; mismatch; diffusion