The chemical and structural evolution within dislocation networks are investigated in a nickel-based single crystal superalloy crept under 1373K and 137MPa. The local region within dislocation networks can be divided to two separated parts: gridlines which compose the arrangements of dislocation networks and mesh regions as intervals between gridlines. With evolution of dislocation networks, precipitation of nano-sized γ′ phase (γ′_n) are observed in mesh region, while gridlines always display the FCC feature of γ phase. The formative mechanism of γ′_n is revealed as increased segregations of Cr, Co and Re along gridlines which enhance the contents of γ′-rich elements such as Al in mesh region to promote the local phase transition from FCC to highly ordered L1₂. However, growth of γ′_n requires massive diffusion of γ′-rich elements that is confined by the chemical barrier along gridlines with strong segregations of Cr, Co and Re. The mesh region of γ′_n and gridlines of γ reinforce each other forming potential γ/γ′ substructures to stabilize the dislocation networks during creep. Denser dislocation networks formed in dendrite core under larger local lattice misfit are accompanied with facilitated formation of γ/γ′ substructures which derive higher creep resistance than interdendritic region.

在1373K和137MPa下蠕变的镍基单晶高温合金中研究了位错网络内的化学和结构演变。错位网络内的局部区域可分为两个独立的部分：组成错位网络的布置的网格线和网格线之间的间隔作为网格区域。与位错网络，纳米尺寸的γ'相（γ'沉淀的进化_Ñ）在网状区域中观察到，而网格线始终显示γ相的FCC特征。γ'的形成机制_Ñ显露作为沿着网格线铬，钴和Re中的增加的偏析，其增强富γ'-元素的含量，如Al啮合区域，以促进从FCC局部相位转换到高度有序的L1 ₂。然而，γ的增长“ _ñ需要由化学屏障局限于沿网格线与铬，钴和Re强偏析丰富γ'元素的大规模扩散。γ的网状区域' _Ñ和γ的网格线相互加强形成潜在γ/γ'的子结构蠕变过程中稳定的位错网络。在较大的局部晶格失配下，在枝晶核心中形成的Denser位错网络伴随着γ/γ'亚结构的容易形成，而γ/γ'亚结构比枝晶间区域具有更高的抗蠕变性。