Diffusion growth of Φ ternary intermetallic compound in the Mg-Al-Zn alloy system:In-situ observation and modeling

摘要

Study on the diffusion growth of ternary intermetallic compounds in Mg-Al-Zn based light-weight alloys is important due to its close interrelation with alloy property.However,there is a very lack of existing data due to difficulties in both experimental and computational aspects.The current work aims at presenting the experimental observation on the diffusion growth behavior of Φ phase at 360℃ as well as calculating its composition-dependent interdiffu sion coefficients.We designed and succes s fully fabricated four Mg-τ ternary diffusion couples annealed at 360℃ for different times,where the diffusion path goes across the Φ phase region and the diffusion growth of ternary intermetallic compound can be solely detected.In-situ observation of the time-dependent growth of Φ phase was performed to accurately determine the parabolic growth constant.The experimental data were then subjected to a numerical inverse method to generate a set of self-consistent interdiffusivities of the ternary intermetallic compounds,which can reproduce the presently observed diffusion growth behavior of Φ ternary intermetallic compound in Mg-τ diffusion couples.