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 °C as well as calculating its composition-dependent interdiffusion coefficients. We designed and successfully fabricated four Mg-τ ternary diffusion couples annealed at 360 °C 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.

研究三元金属间化合物在Mg-Al-Zn基轻合金中的扩散生长非常重要，因为它与合金性能密切相关。然而，由于实验和计算方面的困难，非常缺乏现有数据。目前的工作旨在提供对ϕ相在360°C时扩散生长行为的实验观察，并计算其依赖成分的互扩散系数。我们设计并成功制作了四个在360°C退火不同时间的Mg-τ三元扩散偶，其中扩散路径跨过ϕ相区，并且可以单独检测三元金属间化合物的扩散增长。在-原位观察ϕ相随时间的增长，以准确确定抛物线的生长常数。然后，对实验数据进行数值逆方法处理，以生成三元金属间化合物的一组自洽互扩散性，其可以重现当前观察到的Mg-τ扩散对中三元金属间化合物的扩散生长行为。