Abstract Since half a century ago, researchers have continuously focused on developing γʹ-strengthened Co-base superalloys to achieve an increased power and efficiency; these alloys can supposedly operate at higher temperatures than Ni-base superalloys. However, the yielded results have failed to meet the expectations. Herein, we successfully design novel W-free Co-V-Ta-base alloys by employing machine learning algorithm and CALPHAD methods, which exhibit low mass density (8.67–8.86 g/cm3), an extremely wide γ/γʹ region, a high γʹ solvus temperature (up to 1044 °C), and a high strength. The atom probe tomography results show that titanium is an extremely strong γʹ-former; therefore, it is expected to improve the thermodynamic stability of the γʹ phase. Furthermore, besides the very high tensile strength (18.7 GPa) of γʹ phase, indicated by first-principles calculations, the strength of Ti-incorporated alloy is higher than that of γʹ-strengthened Co-base superalloys; especially, the reported strength value is higher than that of the well-known Co-9Al-9 W alloy by approximately 322 MPa at 750 °C, which is comparable to that of a few commercial Ni-base superalloys. Therefore, the possibility of the Co-V-Ta-base system being a candidate for developing novel Co-base superalloys is strongly suggested in this study.

中文翻译：

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通过机器学习和 CALPHAD 方法加速设计具有极宽 γ/γʹ 区域的新型无 W 高强度钴基高温合金

摘要 半个世纪以来，研究人员一直致力于开发γʹ-强化钴基高温合金，以实现更高的功率和效率。据称，这些合金可以在比镍基高温合金更高的温度下运行。然而，所取得的成果并没有达到预期。在此，我们通过使用机器学习算法和 CALPHAD 方法成功设计了新型无 W Co-V-Ta 基合金，该合金具有低质量密度（8.67-8.86 g/cm3）、极宽的 γ/γʹ 区域、高γʹ固溶线温度（高达1044°C），强度高。原子探针断层扫描结果表明，钛是一种极强的γʹ-前体；因此，有望提高γ′相的热力学稳定性。此外，除了γʹ相具有非常高的抗拉强度（18.7 GPa）外，第一性原理计算表明，掺钛合金的强度高于γʹ-强化钴基高温合金；特别是，报告的强度值在 750°C 时比众所周知的 Co-9Al-9 W 合金高约 322 MPa，与一些商业镍基高温合金的强度值相当。因此，本研究强烈建议 Co-V-Ta 基体系成为开发新型 Co 基高温合金的候选者的可能性。