Abstract Microstructural and chemical heterogeneities may exacerbate the high-temperature mechanical properties of single crystal turbine blades. The evolution of microstructure and compositional homogeneity of an as-cast low Re-containing multicomponent DD6 alloy during through progression of heat treatment was detailedly studied. Using optical microscope, field emission gun scanning electron microscope, electron probe microanalysis, differential scanning calorimetry, and complementary thermodynamic calculations, we investigated the time-dependent size and volume fraction variations of γ/γ′ eutectic during specific solution heat treatment steps, the evolution of γ′ precipitates, carbides, and compositional homogeneity, and the thermo-physical changes of as-cast DD6 alloy during through progression of heat treatment. Based on our experimental and theoretical results, the mechanism underlying the microstructure formation and chemical segregation of as-cast DD6 alloy was clarified. The mechanism of microstructural evolution and compositional homogenization, and the diffusion mechanism of elements that occurs between dendritic and interdendritic regions of as-cast DD6 alloy during through progression of heat treatment were elucidated. The correlations between microstructural evolution, compositional homogenization, and thermo-physical changes of as-cast DD6 alloy during through progression of heat treatment were established.

中文翻译：

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低含 Re-bearing Ni 基单晶高温合金在热处理过程中的显微组织演变和成分均匀化

摘要 微观结构和化学异质性可能会加剧单晶涡轮叶片的高温力学性能。详细研究了铸态低含 Re 多组分 DD6 合金在热处理过程中微观结构和成分均匀性的演变。使用光学显微镜、场发射枪扫描电子显微镜、电子探针微量分析、差示扫描量热法和互补热力学计算，我们研究了特定固溶热处理步骤中 γ/γ' 共晶的随时间变化的尺寸和体积分数变化、演变γ' 析出物、碳化物和成分的均匀性，以及铸态 DD6 合金在热处理过程中的热物理变化。根据我们的实验和理论结果，阐明了铸态 DD6 合金微观结构形成和化学偏析的机制。阐明了显微组织演变和成分均匀化的机制，以及在热处理过程中在铸态 DD6 合金的枝晶和枝晶间区域发生的元素扩散机制。建立了铸态 DD6 合金在热处理过程中的显微组织演变、成分均匀化和热物理变化之间的相关性。阐明了铸态DD6合金在整个热处理过程中在枝晶和枝晶间区域发生的元素扩散机制。建立了铸态 DD6 合金在热处理过程中的显微组织演变、成分均匀化和热物理变化之间的相关性。阐明了铸态DD6合金在整个热处理过程中在枝晶和枝晶间区域发生的元素扩散机制。建立了铸态 DD6 合金在热处理过程中的显微组织演变、成分均匀化和热物理变化之间的相关性。