M. Siddique
材料科学技术（英文）
Mossbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys, such as SS-304L (1.4306S), Incoloy-800H, Incoloy-825, UBHA-25L, Sanicro-28 and Inconel-690, at 1200°C exposed in air and steam environments for 400 h. The basic aim was to identify and compare the iron oxides qualitatively and quantitatively, formed during the oxidation of these alloys in two environments. The behaviour of alloy UBHA-25L in high temperature oxidation in both environments indicates that it has good oxidation resistance especially in steam, whereas Sanicro-28 has excellent corrosion resistance in steam environment. In air oxidation of Inconel-690 no iron oxide, with established MÄossbauer parameters, was detected.
关键词:
Superalloys
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Jian ZHANG
材料科学技术（英文）
An overview of the development and current status of the directional solidification process assisted by liquid metal cooling (LMC) has been presented in this paper. The driving force of the rapid development of the LMC process has been analyzed by considering the demands of (1) newer technologies that can provide higher thermal gradients for alleviated segregation in advanced alloy systems, and (2) better production yield of the large directionally solidified superalloy components. The brief history of the industrialization of the LMC process has been reviewed, followed by the discussion on the LMC parameters including selection of the cooling media, using of the dynamic baffle, and the influence of withdrawal rates and so on. The microstructure and mechanical properties of the traditional superalloys processed by LMC, as well as the new alloys particularly developed for LMC process were then described. Finally, future aspects concerning the LMC process have been summarized.
关键词:
Directional solidification
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王健
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李辰昊
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张铁邦
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李金山
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张平祥
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2014.06.006
利用扫描电镜、X射线衍射分析、能谱分析等手段,从合金成分、热处理组织形貌、界面分布等方面研究了Ni-20Cr-18W基高温合金在900℃温度下25％ NaCl+75％ Na2SO4混合熔融盐中的热腐蚀行为.结果表明:Ni-20Cr-18W基高温合金的腐蚀行为是酸碱熔融机理.腐蚀层呈平面向合金基体推进,无明显择优腐蚀现象发生,主要腐蚀产物为疏松多孔的NiO和Ni3S2腐蚀产物,导致合金表面失去保护性氧化层,增加了腐蚀速度.合金抗热腐蚀性能的降低是因高含量W元素在SO42-作用下腐蚀加剧及第二相粒子与基体的相间腐蚀导致.
关键词:
Ni-Cr-W
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高温合金
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熔盐
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热腐蚀
