Precipitate Behavior Of γ’ Phase In Ni-Al Alloys With The Bulk-diffusion-controlled And The Interface-diffusion-controlled Models

Ni-base superalloy is applied in the high temperature and high pressure circumstances owing to its good high anti-fatigue and oxidation and corrosion resistance performance. Under this circumstance, the atomic of the Ni-base superalloy can accelerate the diffusion and led to the change of the γ’ composition profiles and microstructure, affecting the excellent properties of the materials. Thus, the research of the atomic diffusion is a vital process to obtain a material of desired properties.The bulk-diffusion-controlled and the interface-diffusion-controlled models were established by utilizing the Phase-field. Employing the periodic boundary conditions and the semi-implicit Fourier-spectral method, Ginzburg-Landau and Cahn-Hilliard kinetic equations for numerical solution were solved in the Fourier space to investigate the behavior of γ’ phase in Ni-Al alloys in the different diffusion-controlled.In the bulk-diffusion-controlled, the average particle size of the γ’ phase and the supersaturation of the γ phase increase with the increased diffusivity. At the coarsening stage, the temporal evolution of average radius and the Al concentration follow the relations<r>3～t and CAl～t-1/3, respectively. The fast atomic diffusion promotes the coarsening and restrains the interfacial width.In the interface-diffusion-controlled, the γ’ phase volume fraction, particles radius and the coarsening rate constant were all diminish with the increase of the temperature, the decrease of the composition and the effect of the elastic strain. Furthermore, the γ’ phase volume fraction, particles radius and the coarsening rate constant were all raised than it in the bulk-diffusion-controlled, which is due to the long-range-diffusion of Al atoms in the bulk-diffusion-controlled while it was not in the interface-diffusion-controlled.