Precipitate features including size, morphology, crystal structure, etc., are important parameters determining the performance of precipitate-strengthened alloys. Multiple Fe precipitates were identified in as-cast Cu alloys exhibiting the distinct features, which dramatically influence mechanical properties. However, a complete understanding of precipitation behaviors of Fe particles during casting, in terms of both microscopic kinetics and thermodynamics, remains experimentally challenging. Here, we report the combined implementation of transmission electron microscopy, Thermo-Calc calculations and First-principles calculations to map mechanisms and growth regimes of Fe precipitation in a Cu-Fe-Co system. Our analyses support the idea that to understand the microstructural evolution in the system, both thermodynamic and kinetic arguments must be taken into account. Then, using our multi-approach strategy, the complete picture of the formation and transformation of Fe precipitates is proposed. This work is vital to promote microstructural design for Cu-Fe(-Co) systems, and sheds new insights into understanding of intricate precipitation in alloys.

中文翻译：

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绘制 Cu-Fe-Co 合金铸造过程中多种 Fe 析出物的形成机制和转变机制

析出相特征包括尺寸、形貌、晶体结构等，是决定析出强化合金性能的重要参数。在铸态铜合金中发现了多种铁沉淀物，这些沉淀物表现出独特的特征，极大地影响了机械性能。然而，从微观动力学和热力学角度全面了解铸造过程中铁颗粒的沉淀行为在实验上仍然具有挑战性。在这里，我们报告了透射电子显微镜、Thermo-Calc 计算和第一性原理计算的结合实施，以绘制 Cu-Fe-Co 系统中 Fe 沉淀的机制和生长机制。我们的分析支持这样的观点：为了理解系统的微观结构演化，必须考虑热力学和动力学参数。然后，利用我们的多方法策略，提出了 Fe 沉淀物形成和转变的完整图景。这项工作对于促进 Cu-Fe(-Co) 系统的微观结构设计至关重要，并为理解合金中复杂的沉淀提供了新的见解。