摘要：DZ445合金是新近研制成功的定向凝固镍基高温合金，DZ445合金是在K445合金成分的基础上调整化学成分，并采用定向凝固工艺，发展而成的定向凝固柱晶高温合金。本文采用马弗炉对DZ445合金材料进行820℃和920℃高温氧化处理，并通过X射线衍射（XRD）和带能谱的扫描电镜（SEM/EDS）对氧化不同时间后的氧化试样进行分析，来研究合金元素对DZ445合金高温氧化行为的影响。结果表明：添加的元素在金属表面形成了多种氧化物，其中最主要的是Cr2O3。除此之外，还形成了Al2O3，CoO2、TaO2等氧化物。通过扫描电镜可以观察到，金属表面形成了连续致密的氧化膜，主要是Cr2O3。同时还观察到一些随机分布的氧化物颗粒，结合X射线和能谱可以得出，这些氧化物颗粒主要是TaO2，TiO2，CoO2，是其元素分布不均匀和扩散速度不同导致的。这些氧化物比较疏松，颗粒粗大，容易开裂剥落。截面形貌可以看出，DZ445合金氧化时发生了外氧化和内氧化现象，外层主要为连续且致密的氧化物Cr2O3，内层主要是Al2O3，它会在内部形成楔状氧化物，产生“钉扎作用”，使氧化膜与基体结合的更加牢固。78788

毕业论文关键词：DZ445合金；定向凝固；镍基高温合金；高温氧化

Effect of Alloying Elements on High Temperature Oxidation Behavior of DZ445 Alloy

Abstract：DZ445 alloy is a newly developed directional solidification of nickel-based superalloy,DZ445 alloy is in the K445 alloy composition based on the adjustment of chemical composition,And the use of directional solidification process,Development of directional solidification column crystal superalloy。In this paper, DZ445 alloy material was subjected to high temperature oxidation treatment at 820 ℃ and 920 ℃,The oxidized samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM / EDS) with different energy spectra,To study the effect of alloying elements on the oxidation behavior of DZ445 alloy at high temperature。The results show：The added elements form a variety of oxides on the metal surface,One of the most important is Cr2O3。In addition,Also formed Al2O3, CoO2, TaO2 and other oxides。By scanning electron microscopy can be observed, the metal surface to form a continuous dense oxide film, mainly Cr2O3。At the same time, it is also observed that some randomly distributed oxide particles, combined with X-ray and energy spectrum can be drawn, these oxide particles are mainly TaO2, TiO2, CoO2, its uneven distribution of elements and diffusion rate caused by different。 These oxides are relatively loose, coarse particles, easy to peel off。 Sectional morphology can be seen, DZ445 alloy oxidation occurred when the external oxidation and internal oxidation phenomenon, the outer layer is mainly continuous and dense oxide Cr2O3, the main layer is Al2O3, it will form a wedge-shaped oxide in the internal, resulting in "nails Bar role ", so that the oxide film and the matrix of the more solid。

Key words：DZ445 alloy;Directional solidification;Nickel-based superalloy;High temperature oxidation

目录

1 绪论 1

1。1 高温合金 1

1。2 高温合金的应用及性能要求 1

1。3 高温合金分类 2

1。4 定向凝固镍基高温合金 3

1。5 金属氧化阶段 4

1。6 研究目的及意义 5

2 实验方法 6

2。1 实验材料 6

2。2 实验方法 6

2。3 实验设备及材料