Microstructural characterization of a new mechanically alloyed Ni-base ODS superalloy powder
Microstructural characterization of a new mechanically alloyed Ni-base ODS superalloy powder
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DOI：
10.1016/j.matchar.2014.12.008
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发表时间：
2015-02
影响因子：
4.7
通讯作者：
S.M.S. Aghamiri;H. Shahverdi;S. Ukai;N. Oono;K. Taya;S. Miura;S. Hayashi;T. Okuda
中科院分区：
文献类型：
--
作者：
S.M.S. Aghamiri;H. Shahverdi;S. Ukai;N. Oono;K. Taya;S. Miura;S. Hayashi;T. Okuda
研究了机械合金化工艺后用于高温燃气轮机应用的新型镍基氧化物弥散强化高温合金粉末的微观结构。在这项研究中，将成分与 CMSX-10 高温合金相似的雾化粉末与氧化钇和铪粉末机械合金化。机械合金化粉末仅含有过饱和固溶体γ相，没有剧烈塑性变形提供的γ'和氧化钇，而经过三步时效后，由于Al和Ta分配到γ'相，Co、Cr、Re、W和Mo分配到γ相，析出γ'相。机械合金化将 γ' 的形貌修改为新的相干 γ-γ' 纳米级层状结构，以最大限度地减少析出物的弹性应变能，从而在高温下产生 0.16% 的低晶格失配。 γ'片层优先沿弹性软[100]方向排列。此外，通过将 Hf 从大的非共格 YAlO3 添加到细小的半共格 Y2Hf2O7 氧化物颗粒（平均尺寸为 7 nm，颗粒间距为 76 nm），在 γ 相中细化了沉淀的氧化物颗粒。
The microstructure of a new Ni-base oxide dispersion strengthened superalloy powder was studied for high temperature gas turbine applications after the mechanical alloying process. In this study, an atomized powder with a composition similar to the CMSX-10 superalloy was mechanically alloyed with yttria and Hf powders. The mechanically alloyed powder included only the supersaturated solid solution γ phase without γ′ and yttria provided by severe plastic deformation, while after the 3-step aging, the γ′ phase was precipitated due to the partitioning of Al and Ta to the γ′ and Co, Cr, Re, W, and Mo to the γ phase. Mechanical alloying modified the morphology of γ′ to the new coherent γ–γ′ nanoscale lamellar structure to minimize the elastic strain energy of the precipitation, which yielded a low lattice misfit of 0.16% at high temperature. The γ′ lamellae aligned preferentially along the elastically soft [100] direction. Also, the precipitated oxide particles were refined in the γ phase by adding Hf from large incoherent YAlO3to fine semi-coherent Y2Hf2O7oxide particles with the average size of 7 nm and low interparticle spacing of 76 nm.