Effect of thermal history on microstructural changes in aluminized nickel-based single-crystal superalloy
Effect of thermal history on microstructural changes in aluminized nickel-based single-crystal superalloy
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DOI：
10.2320/jinstmet.76.402
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发表时间：
2013-12
影响因子：
--
通讯作者：
K. Kasai;H. Murakami;K. Noda
中科院分区：
文献类型：
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作者：
K. Kasai;H. Murakami;K. Noda
研究了热史对渗铝和铂渗铝镍基单晶高温合金微观结构变化的影响。首先对高温合金基体进行电解抛光，以消除残余表面应变。然后，对部分基体进行电沉积 Pt 和真空退火，并使用常规渗铝工艺制备渗铝和 Pt 渗铝样品。研究发现，在镀铝样品中，在热循环加热过程中，在基材/涂层界面附近形成了空隙，而等温加热则形成了二次扩散区（SDZ）。镀铝样品的这些不同的微观结构变化可以通过加热/冷却过程中涂层和基材之间的扩散动力学来解释。另一方面，在 Pt 渗铝样品中，在热循环和等温处理后观察到二次反应区 (SRZ) 的形成。这些结果可以通过退火过程中衬底表面的多晶化来解释，这促进了相互扩散，从而形成了 SRZ。 [doi:10.2320/matertrans.M2013205]
The effect of the thermal history on microstructural changes in aluminized and Pt-aluminized Ni-based single-crystal superalloys was investigated. The superalloy substrates were first electropolished to get rid of the residual surface strain. Then, Pt was electrodeposited and vacuum annealing was conducted for some of the substrates, and aluminized and Pt-aluminized specimens were prepared using the conventional aluminizing process. It was found that in the aluminized specimens, voids were formed in the vicinity of the substrate/coating interfaces during thermal cyclic heating, whereas secondary diffusion zones (SDZ) were formed by isothermal heating. These different microstructural changes of the aluminized specimens can be explained by the kinetics of diffusion between the coating layer and the substrate during the heating/cooling processes. In the Pt-aluminized specimen, on the other hand, secondary reaction zone (SRZ) formation was observed after both thermal cyclic and isothermal treatments. These results can be explained by the polycrystallization of the substrate surface during the annealing process, which promotes interdiffusion, resulting in the formation of an SRZ. [doi:10.2320/matertrans.M2013205]