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

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 phi phase at 360 degrees C as well as calculating its composition-dependent interdiffusion coefficients. We designed and successfully fabricated four Mg-tau ternary diffusion couples annealed at 360 degrees C for different times, where the diffusion path goes across the phi phase region and the diffusion growth of ternary intermetallic compound can be solely detected. In-situ observation of the time-dependent growth of phi 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 phi ternary intermetallic compound in Mg-tau diffusion couples. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The study focused on the diffusion growth of ternary intermetallic compounds in Mg-Al-Zn based light-weight alloys, presenting experimental observations and calculating composition-dependent interdiffusion coefficients. The results successfully verified the diffusion growth behavior by generating self-consistent interdiffusivities of the ternary intermetallic compounds.