论文部分内容阅读
通过光学显微镜、X射线衍射、扫描电镜和热重分析等研究了添加钇对Fe-Si合金在900℃和1000℃、0.1 MPa纯氧气中高温氧化行为的影响。结果表明,随着元素钇含量的增加,Fe-3Si-0.5Y和Fe-3Si-5.0Y合金的晶粒尺寸较Fe-3Si-0Y合金降低约80%和94%,同时,根据X射线分析结果,合金表面氧化膜的晶粒尺寸随着合金晶粒尺寸的降低明显减小。晶粒细化使合金及其氧化膜中的晶界数量增加,并进一步地促进了合金元素和氧在其中的扩散以及SiO2和Y2O3的形成。然而,含钇合金在900℃和1000℃氧化时均未生成单一连续的SiO2或Y2O3氧化层,但晶粒细化后硅和钇氧化物的快速形成及部分地横向连接对元素的扩散仍起到了比较有效的抑制作用,含钇合金的氧化抗力因此得到了提高。讨论了添加元素钇导致的合金晶粒细化对Fe-Si合金氧化行为的影响机制。
The effects of adding yttrium on the high-temperature oxidation behavior of Fe-Si alloy at 900 ℃, 1000 ℃ and 0.1 MPa pure oxygen were investigated by optical microscope, X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. The results show that the grain size of Fe-3Si-0.5Y and Fe-3Si-5.0Y alloys decreases by about 80% and 94%, respectively, compared with that of Fe-3Si-0Y alloy as the content of yttrium increases. As a result, the grain size of the oxide film on the surface of the alloy decreases significantly as the grain size of the alloy decreases. The grain refinement increases the number of grain boundaries in the alloy and its oxide film and further promotes the diffusion of alloying elements and oxygen therein and the formation of SiO2 and Y2O3. However, no single continuous SiO2 or Y2O3 oxide layer was formed during the oxidation of the Y-containing alloys at 900 ° C and 1000 ° C. However, the rapid formation of the grain-refined Si and Yttrium oxide and the partial lateral diffusion of the elements still To a more effective suppression, the oxidation resistance of yttrium-containing alloys has therefore been improved. The mechanism of grain refinement induced by addition of yttrium on the oxidation behavior of Fe-Si alloys was discussed.