Institute of Applied Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany.
Nat Commun. 2013;4:2955. doi: 10.1038/ncomms3955.
Phase separation of γ' precipitates determines the microstructure and mechanical properties of nickel-based superalloys. In the course of ageing, disordered γ spheres form inside ordered (L12) γ' precipitates, undergo a morphological change to plates and finally split the γ' precipitates. The presence of γ particles inside γ' affects coarsening kinetics and increases alloy hardness. Here we use atom probe tomography to visualize phase separation in a Ni86.1Al8.5Ti5.4 alloy in three dimensions and to quantify the composition of all the phases with near-atomic resolution. We find that γ' precipitates are supersaturated in nickel, thereby driving the formation of γ particles and observe a compositional evolution of the γ particles, which accompanies their morphological change. Our results suggest that by controlling nickel supersaturation we can tailor the phase separation and thereby the properties of nickel-based superalloys.
γ' 析出相的相分离决定了镍基高温合金的微观结构和力学性能。在时效过程中，无序的 γ 球体会在有序的（L12）γ' 析出相中形成，经历形态变化成板状，最终使 γ' 析出相分裂。γ 相的存在会影响 γ' 相的粗化动力学，并增加合金的硬度。在这里，我们使用原子探针层析技术在三维空间中可视化 Ni86.1Al8.5Ti5.4 合金中的相分离，并以近原子分辨率定量分析所有相的组成。我们发现 γ' 析出相在镍中过饱和，从而促使 γ 相的形成，并观察到 γ 相的组成演变，伴随着其形态的变化。我们的结果表明，通过控制镍的过饱和度，我们可以调控相分离，从而调控镍基高温合金的性能。
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