Cr-rich nanosize precipitates in a standard heat-treated Inconel 738 superalloy
Cr-rich nanosize precipitates in a standard heat-treated Inconel 738 superalloy
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DOI：
10.1080/14786430903270643
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发表时间：
2010-02
影响因子：
1.6
通讯作者：
Huairuo Zhang;O. Ojo
中科院分区：
文献类型：
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作者：
Huairuo Zhang;O. Ojo
分析透射电子显微镜研究的性质的纳米尺寸的第二相沉淀物中形成的标准热处理的商业镍基高温合金IN 738。除M5B3硼化物和M23C6碳化物外，还发现沉淀物由M2B型硼化物相的颗粒组成，这在合金中以前未报道，在镍基高温合金中也很少报道。M2B硼化物具有体心四方晶和面心斜方晶的双重晶体结构。电子衍射图案和高分辨率透射电子显微镜图像的分析表明，这两种晶体结构可以共存于一个单一的M2B颗粒作为共生与平面缺陷的形成。阐明了热处理合金中微观相之间的晶体学关系，并讨论了硼化物对高温材料加工（如激光束处理）过程中抗晶界液化开裂性能的影响。
An analytical transmission electron microscopy study was performed on the nature of nanosize secondary phase precipitates that form in standard heat-treated commercial nickel base superalloy IN 738. In addition to M5B3 borides and M23C6 carbides, the precipitates were found to also consist of particles of M2B-type boride phase, which is previously unreported in the alloy and rarely reported in nickel base superalloys. The M2B borides exhibited a dual crystallographic structure: body centered tetragonal and face centered orthorhombic. Analyses of electron diffraction patterns and high-resolution transmission electron microscopy images indicated that both crystal structures can co-exist in a single M2B particle as an intergrowth with the formation of planar defects. Crystallographic relationship between microconstituent phases in the heat-treated alloy were elucidated and the influence of the borides on resistance to grain boundary liquation cracking during high-temperature material processing, such as laser beam treatment, is discussed.