Phase equilibria of the Al-Co-Ta ternary system over the whole composition range at 1200 °C and 1300 °C were experimentally determined from the equilibrated alloys using electron probe microanalysis, scanning electron microscopy, and X-ray diffraction. The measured results indicate that, at 1200 °C, the addition of Al can stabilize the λ₁-Co₂Ta phase (Laves C14-type), which is absent in binary system, and forms a broad phase region parallel to the Al-Co axis in the Al-Co-Ta ternary isothermal sections. The ternary compound of the Heusler phase AlCo₂Ta (L2₁-type) was confirmed at both investigated isothermal sections with the composition range about 49.7–55.7 at% Co and 14.7–23.6 at% Ta. In addition, a large solubility of Al was identified in the μ-Co₆Ta₇ phase. Based on the experimental results, the published data of the Al-Co and Al-Ta binary systems, and the reassessed Co-Ta parameters from the current work, a thermodynamic assessment of the Al-Co-Ta system was undertaken using the CALPHAD technique. A set of reliable thermodynamic parameters for the Al-Co-Ta system was obtained with a satisfactory agreement with the experimental data. The calculated liquidus projection and invariant reaction scheme in the Al-Co-Ta ternary system were presented. The present work can provide essential experimental and thermodynamic data for the establishment of the Co-based alloy database.

使用电子探针显微分析、扫描电子显微镜和 X 射线衍射从平衡的合金实验确定了 Al-Co-Ta 三元体系在 1200°C 和 1300°C 的整个组成范围内的相平衡。实测结果表明，在 1200 ℃时，Al 的加入可以稳定二元体系中不存在的 λ ₁ -Co ₂ Ta 相（Laves C14 型），并形成与 Al- 平行的宽相区。 Al-Co-Ta 三元等温截面中的 Co 轴。Heusler相的三元化合物AlCo ₂ Ta (L2 ₁型）在两个研究的等温部分都得到证实，成分范围约为 49.7-55.7 at% Co 和 14.7-23.6 at% Ta。此外，Al在μ-Co ₆ Ta _{7中的溶解度很大。}阶段。基于实验结果、已发表的 Al-Co 和 Al-Ta 二元系统数据以及从当前工作中重新评估的 Co-Ta 参数，使用 CALPHAD 技术对 Al-Co-Ta 系统进行了热力学评估. 得到了一组可靠的Al-Co-Ta体系热力学参数，与实验数据吻合较好。给出了计算得到的Al-Co-Ta三元体系液相线投影和不变反应方案。目前的工作可以为钴基合金数据库的建立提供必要的实验和热力学数据。