Ordered Ni

3

Al intermetallic precipitates constitute the main hardening sources of Ni-based superalloys. Here

we report the interdiffusion and precipitation behavior in a Ni/Ni

3

Al model system. The deposition of Ni

3

Al on a pure Ni layer at 500°C generated L1

2

-structured γ′ (Ni

3

Al) precipitates

preferentially at the interface. After annealing at 800°C for 1 h

interdiffusion between Ni and Ni

3

Al layers occurred

and the γ′ precipitates that grew near the parent Ni/Ni

3

Al interface are ∼2.8 times larger in size than those formed in the matrix. Monte Carlo simulations indicate that vacancies preferentially diffuse along the Ni/Ni

3

Al interface

increasing the probability of precipitation.