He Runjun, Li Miao, Han Xiao, Feng Wei, Zhang Hongye, Xie Huimin, Liu Zhanwei
AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China.
School of Technology, Beijing Forestry University, Beijing 100083, China.
Nanomaterials (Basel). 2023 Feb 2;13(3):608. doi: 10.3390/nano13030608.
The interface plays an important role in determining strength and toughness in multiphase systems and the accurate measurement of the interface structure in single crystal (SX) Ni-based superalloy is also essential. In this work, the γ and γ' lattice constant, γ/γ' interface width at dendritic and interdendritic region of casting and solution treatment SX Ni-based superalloy is measured. Various advanced equipment is used to characterize γ/γ' interface nanostructure. A typical correlation between interface width and γ/γ' misfit is also summarized. The interface width in the dendritic region of the as-cast sample is larger than that in the interdendritic region. The misfit in the dendritic region is larger than that in the interdendritic region, which has a trend of negative development. There is a common law of the as-cast interdendritic and dendrite interface sample, where the absolute value of the misfit between the two phases is increasing with the phase interface broadening. The comparison of the as-cast and heat-treated interdendritic sample shows that after heat treatment, the phase interface width increases, the misfit decreases, the lattice constant of γ phase increases, and the lattice constant of the γ' phase decreases. By comparing the as-cast and heat treated dendrites, the absolute value of the misfit of the as-cast dendrite sample is significantly smaller than that of the heat-treated sample, and the misfit increases with the interface broadening. The comparison between interdendritic and dendritic heat-treated samples shows that the absolute value of the misfit between the two phases is smaller than that of the dendritic as-cast samples, and the absolute value of the misfit also increases with the phase interface broadening. In conclusion, property heat treatment can significantly increase the lattice constants of the γ and γ' phases, reduce the lattice mismatch at the interface of the two phases, and improve the high temperature stability of the alloy. A better understanding of the microstructure of Ni-based single crystal superalloys will provide guidance for the subsequent design of more advanced nickel-based single-crystal superalloys.
界面在多相系统强度和韧性的决定中起着重要作用，准确测量单晶（SX）镍基高温合金中的界面结构也至关重要。在本工作中，测量了铸造及固溶处理后的SX镍基高温合金枝晶和枝晶间区域的γ和γ'晶格常数、γ/γ'界面宽度。使用了各种先进设备来表征γ/γ'界面纳米结构。还总结了界面宽度与γ/γ'错配之间的典型相关性。铸态样品枝晶区域的界面宽度大于枝晶间区域的界面宽度。枝晶区域的错配比枝晶间区域的错配大，且有负向发展趋势。铸态枝晶间和枝晶界面样品存在一个共同规律，即两相之间错配的绝对值随着相界面变宽而增大。铸态和热处理后的枝晶间样品的比较表明，热处理后，相界面宽度增加，错配减小，γ相的晶格常数增加，γ'相的晶格常数减小。通过比较铸态和热处理后的枝晶，铸态枝晶样品错配的绝对值明显小于热处理样品，且错配随着界面变宽而增大。枝晶间和枝晶热处理样品的比较表明，两相之间错配的绝对值小于枝晶铸态样品，且错配的绝对值也随着相界面变宽而增大。总之，性能热处理可显著增加γ和γ'相的晶格常数，降低两相界面处的晶格失配，提高合金的高温稳定性。更好地理解镍基单晶高温合金的微观结构将为后续更先进的镍基单晶高温合金的设计提供指导。
