The Effect of Temperature and Misfit on γ′ Precipitation in Co-Ti Alloys: Phase-Field Modeling and Experiments

The effect of temperature and misfit on the coarsening behaviors of γ′ phase in the Co-12.5Ti alloy is studied by means of experimental observations and phase-field simulation. The experimental and simulated results show that the morphologies of γ′ phase evolve from spherical shape to rectangle shape as the aging time increases. Additionally, the average inter-precipitate distance increases with the temperature rises. Both the mean particle sizes and aspect ratio are increasing with the increasing of the temperature and misfit. The coarsening rate of γ′ phase obtained from simulations is 1.37 and 6.48 nm3/min for 700 and 750 °C, respectively, which is close to the results obtained from experiments. The coarsening rate of γ′ phase reduces as the misfit decreases at 750 °C. The simulation results are in good agreement with the experimental results.