Temperature gradient driving interdiffusion interface and composition evolution in Ni–Al–Cr alloys
Yongsheng Li, Hui-Yu Wang, Jing Chen, Shuaige Yang, Peng Sang, Hongli Long
Abstract
Abstract The interdiffusion interface microstructures and composition evolution of Ni–Al–Cr/Ni–Al–Cr layered alloys under different temperature gradients were studied using phase‐field simulation. A precipitate‐free zone forms near the interface of the layered alloys, and the interface does not move with time under temperature gradients. When Cr concentrations in the alloy layers are different, Al diffuses from a low‐ to high‐temperature region, whereas Cr from a high‐ to low‐temperature region. The width of the precipitate‐free zone changes from 0.5 to 2.5 μm as the temperature gradient changes from Δ T = 0.625 K·μm −1 to 1.250 K·μm −1 ; the width of the interdiffusion zone is also enlarged. Additionally, the temperature gradient promotes the interdiffusion of elements through the interface. In contrast, when the initial Al concentration is different in the alloy layers, an uphill diffusion of Al occurs, which is driven by the chemical potential of Al.