毕业论文移动版

摘要：本论文主要研究了Zr-Sn-Nb-Fe-O合金中的合金Si对高压釜腐蚀性能的影响以及其对腐蚀的影响机理。我们通过对合金的微观结构的观察以及对他们的氧化物性能的定量分析发现含Si元素的合金具有更好的耐腐蚀性。其中的原因是Si元素细化了第二相粒子，降低了合金的再结晶度，并且提高了合金的强度。在发生腐蚀行为的过程中，氧化膜和金属基体的界面处会产生巨大的应力，这种应力使得金属基体发生形变，而该形变产生的波状起伏界面会伴随有裂纹的生成。强度更高的合金界面其波状起伏演化会比较慢，且裂纹出现的时间会较晚。但是，加入微量Si元素并不会明显改变氧化膜的敏感性。所以，含Si元素的合金发生腐蚀动力学转变的时间比不含Si元素的合金晚，其耐腐蚀性能也随之得到提升。在研究中我们发现，在腐蚀动力学转变发生之前，几乎所有的裂纹都产生在波状起伏界面的波峰上面，而发生腐蚀动力学转变之后，由于与金属基体相互作用的氧化膜层厚度有所减少，界面处的机械能降低，界面处的波状起伏再次变得平缓。关键词：锆合金；耐腐蚀性；微观结构；第二相粒子；氧化膜

ABSTRACT：This paper investigates the effect of alloyed Si on the autoclave corrosion performance and corrosion mechanisms of Zr–Sn–Nb–Fe–O alloys. Quantitative analyses are performed on the microstructure  of alloys and their oxide behavior. The Si-containing alloy possesses improved corrosion resistance.Adding a trace of Si into Zr-0.5 Sn-0.4 Nb-0.3 Fe-0.08 O alloy could refine SPPs, decrease the degree of recrystallization and enhance the strength of alloy. During corrosion process, large stress was produced at oxide/metal  interface due to  the great volume difference between oxide and the consuming metal matrix. This stress led to the deformation of metal matrix and produced undulated interface which associated formation of cracks. The evolution  of undulated interface was slower in the alloy with higher strength. However, a trace of alloyed Si would not modify the susceptibility of the oxide at a noticeable extent. Therefore, the corrosion kinetics transition of the Si-containing alloy was postponed.Before corrosion kinetics transition, almost all cracks appeared above the crests of undulated interface.After corrosion kinetics transition, the thickness of oxide which interacted with metal matrix reduced and the mechanical energy at interface decreased correspondingly. Hence, the undulations became mild again.

Keywords: zirconium alloy ， corrosion resistance ， microstructure ，second phase particles, oxide film

目录

第一章绪论 1

1.1研究背景和意义 1

1.1.1锆合金的应用和其重要性 1

1.1.2研究意义 2

1.2国内外研究的现状 3

1.2.1锆合金的性能及发展现状 3

1.2.2锆合金的研究方法 5

1.2.3锆合金中的第二相 6

1.2.4锆合金成分对其组织性能的影响 9

1.3研究主要内容 10

第二章实验方法 12

2.1实验材料 12

2.2实验方案 13

2.2.1低温预变形实验 13

2.2.2二次β水淬实验 13

2.2.3高压釜腐蚀实验 (责任编辑：qin)