镍基高温合金γ′相微观形貌演化的蒙特卡洛模拟研究

    Study on γ′-phase Micromorphology Evolution of Nickel-based Superalloy with Monte Carlo Simulations

    • 摘要: 镍基单晶高温合金因其卓越的高温强度、抗蠕变性能及热稳定性,被广泛应用于航空航天和能源领域。由于温度对镍基高温合金γ'-Ni3Al析出相形貌的微观影响尚不明确,所以采用集团展开和蒙特卡洛模拟相结合的方法,在原子尺度上系统研究了温度对Ni0.87Al0.13模型高温合金中γ'-Ni3Al析出相形貌结构的影响。结果表明,在200 K时γ'析出相颗粒形貌呈现由六个100晶面构成的截角八面体状;随着温度升高至300 K,γ'析出相转变为层片状,γ'相与γ相之间的界面平直清晰;随着温度进一步升高,γ'相开始逐渐溶解,γ'相内Al原子的浓度随之开始下降。最终在1100 K时γ'相完全回溶消失、形成Ni0.87Al0.13无序固溶体。该研究可为深入理解镍基单晶高温合金的微观组织演化规律及内在机理提供理论依据,也可为该合金的工艺优化和工程应用提供参考依据。

       

      Abstract: Nickel-based single-crystal superalloys are widely used in aerospace and energy applications due to their excellent high-temperature strength, creep resistance, and thermal stability. As the effects of temperature on the morphology and structural evolution of γ'-Ni3Al precipitates in nickel-based superalloys remain unclear, a combined method of cluster expansion and Monte Carlo simulations was adopted in this study to systematically investigate the atomic-scale morphological and structural changes of γ'-Ni3Al precipitates in the Ni0.87Al0.13 single-crystal superalloy model. The results show that at 200 K, the particle morphology of γ' precipitated phase presents a truncated octahedral shape consisting of six100 crystalline surfaces; as the temperature increases to 300 K, the γ' precipitated phase transforms into a lamellar shape, and the interface between the γ' phase and the γ phase is straight and clear; with the further increase of the temperature, the γ' phase starts to dissolve gradually, and the concentration of the Al atoms within the γ' phase begins to decrease subsequently. Finally, at 1100 K, the γ' phase completely dissolves and disappears, forming a Ni0.87Al0.13 uniform and disordered solid solution. This work provides a theoretical basis for revealing the evolution rules and internal mechanism microstructures in nickel-based single-crystal superalloys, and offers useful reference for the process optimization andengineering application of the alloys.

       

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