NiAl-Cr(Mo)-Ti合金的高温氧化行为的研究
关键词： NiAl金属间化合物；高温氧化；氧化动力学;毕业论文
The study on high temperature oxidation behavior of NiAl-Cr(Mo)-Ti alloy
Abstract: NiAl intermetallic compound alloy is ideal new high-temperature structural materials for the aviation aircraft, engines and other automotive because of its high melting point, low density, strong oxidation resistance and high thermal conductivity. Poor room temperature ductility and high temperature strength have been significantly improved by adding the alloy elements and the microstructure regulation and other means. The 33Ni32Al-28Cr (3Mo)-4Ti alloy was chosen as experimental materials to study the alloy at 900℃ high temperature oxidation behavior in air, and then use the X-ray diffraction (XRD) and scanning electron spectroscopy equipped microscope (SEM ) to characterize its oxide film to study the oxidation process and the oxidation mechanism, the influence of its alloying elements on high temperature oxidation resistance was discussed. The experimental results showed that the oxidation kinetics of the alloy at 900℃ approximately obey the parabolic law. By XRD and SEM analysis, that the oxide film is mainly composed of Cr2O3, Al2O3 and a small amount of TiO2 .
Keywords:NiAl intermetallic compound; High temperature oxidation; Oxidation kinetics
目 录
1 绪论 1
1.1 NiAl基高温合金的发展背景及进程 1
1.2 NiAl基合金的物理性质 1
1.3 NiAl金属间化合物研究发展方向 3
1.4 金属高温氧化概述 3
1.4.1 金属氧化膜的形成 3
1.4.2 金属氧化膜的组成 4
1.4.3 金属高温氧化 4
1.4.4 金属氧化热力学 5
1.4.5 抛物线生长动力学的Wagner理论 6
1.4.6 NiAl基合金氧化机理讨论 7
1.5 研究本课题的目的与意义 9
2 实验方法 10
2.1 试验合金 10
2.2 试验内容 10
2.2.1 试样制备及氧化实验前准备工作 10
2.2.2 高温氧化实验 10
2.2.3 样品氧化膜的表征 11
2.3 主要实验设备 11
2.3.1 马弗炉 11
2.3.2 电子天平 11
2.3.3 X射线衍射仪 12
2.3.4 扫描电子显微镜(scanning electron microscopy，SEM) 13
2.3.5 镶嵌机 14
2.3.6 其它实验用品 15
3 实验结果与讨论 16
3.1 试验合金NiAl-Cr(Mo)-Ti的显微组织 16
3.2 恒温氧化动力学曲线及分析 17
3.3 氧化产物的XRD物相分析 18
3.4 NiAl合金的氧化膜表面形貌分析 19
3.5 NiAl合金的氧化膜横截面分析 22
4 结论 23
致谢 24