In-situ environmental TEM study of γ′-γ phase transformation induced by oxidation in a nickel-based single crystal superalloy
In-situ environmental TEM study of γ′-γ phase transformation induced by oxidation in a nickel-based single crystal superalloy
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DOI：
10.1016/j.jallcom.2015.07.017
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发表时间：
2015-12-05
影响因子：
6.2
通讯作者：
Zhang, Ze
中科院分区：
文献类型：
--
作者：
Ding, Qingqing;Shen, Zhenju;Zhang, Ze
高温合金的高温氧化诱发γ '相向γ相的转变严重影响了高温合金的蠕变性能，利用原位环境透射电镜、能谱仪和电子能量损失谱仪对高温合金的高温氧化诱发γ'相向γ相的转变进行了详细的研究。原位观察表明，在氧化过程中，有序γ '相（L1（2））逐渐转变为无序γ相（面心立方（fcc）），氧化产物由γ-Al_2 O_3微晶组成，具有较强的晶体学织构。这直接证明了γ ′-γ相变是由铝氧化引起的，γ ′相中的铝贫化。此外，氧被证明优先通过γ ′-γ相界面扩散，这与以前认为的（g基质）不同。(C)2015爱思唯尔B. V.保留所有权利。
Oxidation induced phase transformation from gamma' to gamma phase can severely degrade creep properties of superalloys and has been studied by in-situ environmental transmission electron microscopy, energy dispersive spectrometer and electron energy loss spectroscopy in detail. The in-situ observation showed that, during oxidization, the ordered gamma' phase (L1(2)) gradually transformed to disordered gamma phase (face-centered cubic (fcc)) with the appearance of oxidation product consisted of gamma-Al2O3 crystallites with a strong crystallographic texture. This directly proves that gamma'-gamma phase transformation are induced by aluminum oxidation with aluminum depleted in gamma' phase. Furthermore, the oxygen was demonstrated to diffuse preferentially through gamma'-gamma phase interface which is different from previously thought (g matrix). (C) 2015 Elsevier B.V. All rights reserved.