AI 中文总结
研究纳米结构Inconel 725合金热处理中相形核与演化路径，通过固溶和时效处理，利用缺陷结构控制相选择和析出路径，实现同时析出强化和晶粒稳定，为定制微观结构和协同强化提供策略。
AI 中文摘要
物理气相沉积能够制造具有独特缺陷结构的纳米结构高温合金，但其相演化路径可能与传统加工合金有显著差异。本研究系统研究了固溶和时效处理对具有初始均匀柱状纳米孪晶结构的溅射Inconel 725薄膜中相选择和偏析行为的影响。相对低温下的直接时效促进了孪晶界和富缺陷区域大量δ相析出，消耗了γ基体中的Nb并抑制了γ'/γ''析出。高温固溶处理诱导再结晶并消除纳米孪晶结构，显著减少δ相析出并增加Nb可利用性，使在细化的γ基体（<1μm）中形成超细球形γ'/γ''析出物。后续时效处理促进元素分配并推动γ'/γ''析出物从球形向透镜状形态演变，而δ析出物沿晶界越来越集中。这种晶内γ'/γ''和晶界δ相的空间分离实现了同时析出强化和晶粒稳定，硬度值接近9 GPa。整体而言，本研究表明缺陷结构提供的初始模板可控制相选择和析出路径，为定制纳米结构高温合金的微观结构和实现协同强化提供了策略。
英文摘要
Physical vapor deposition enables the fabrication of nanostructured superalloys with unique defect architectures, yet their phase evolution pathways can differ significantly from those of conventionally processed alloys. In this study, the effects of solution and aging treatments on phase selection and precipitation behavior in sputtered Inconel 725 films with an initially uniform columnar nanotwinned structure were systematically investigated. Direct aging at relatively low temperatures promoted extensive δ-phase precipitation at twin boundaries and defect-rich regions, which depleted Nb from the γ matrix and suppressed γ'/γ" precipitation. In contrast, high-temperature solution treatment induced recrystallization and eliminated the nanotwinned structure, significantly reducing δ-phase precipitation and increasing Nb availability to enable the formation of ultrafine spherical γ'/γ" precipitates within a refined γ matrix (<1 μm). Subsequent aging treatments promoted elemental partitioning and drove the morphological evolution of γ'/γ" precipitates from spherical to lenticular forms, while δ precipitation became increasingly concentrated along grain boundaries. This spatial separation of intragranular γ'/γ" and grain-boundary δ phases enabled simultaneous precipitation strengthening and grain stabilization, resulting in hardness values approaching 9 GPa. As a whole, this study demonstrates that the initial templates provided by defect structures can govern phase selection and precipitation pathways, providing a strategy for tailoring microstructure and achieving synergistic strengthening in nanostructured superalloys.
