材料工程2025，Vol.53Issue(9)：65-73,9.DOI:10.11868/j.issn.1001-4381.2023.000876
镍基铸造高温合金K444在1000℃长期热暴露形成的多层膜结构
Multilayer structure formed by long-term thermal exposure of nickel-based cast superalloy K444 at 1000℃
摘要
Abstract
To investigate the formation of multilayer structures in high-temperature components of gas turbines,extensive long-term thermal exposure experiments are conducted on nickel-based casting superalloy K444 at 1000℃in air.The morphology,structure,and composition of the multilayer structure on both the surface and cross-section of the alloy are meticulously characterized and analyzed using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and X-ray diffraction(XRD).The results show that the multilayer structure of the K444 alloy comprises an outermost continuous oxide layer predominantly of Cr2O3,interspersed with minor amounts of TiO2 and NiO,a subsurface discrete oxide layer of Al2O3,and an innermost layer enriched with TiN.The thickening curve of the alloy oxide film during thermal exposure adheres to the parabolic law,and the thickening rate of the oxide film gradually decreases as the thermal exposure progresses.The outermost dense oxide layer of Cr2O3 formed due to its lower thermal expansion coefficient,serving as a significant barrier to oxygen penetration.The scarcity of Al in the oxide layer,attributed to its lower diffusion coefficient,leads to its aggregation in the sub-outer layer,forming a discrete inner oxide layer.Furthermore,a competitive reaction between oxygen and nitrogen occurres in the innermost layer of the alloy.As the partial pressure of oxygen decreases and the partial pressure of nitrogen relatively increases,the Ti element undergoes a nitriding reaction to form TiN,which subsequently oxidizes to TiO2 as oxidation progressed.The research findings elucidate the formation mechanism of the multilayered film structure of K444 and the process of long-term thermal exposure at 1000℃,providing a theoretical foundation for its further application at high temperatures.关键词
镍基铸造高温合金/多层膜结构/高温氧化/氧化动力学/TiNKey words
nickel-based cast superalloy/multilayer structure/high-temperature oxidation/oxidation kinetics/TiN分类
管理科学引用本文复制引用
谢由水,李晓鹏,赵义瀚,孙彦文,王宇奇,赵成志..镍基铸造高温合金K444在1000℃长期热暴露形成的多层膜结构[J].材料工程,2025,53(9):65-73,9.基金项目
宁波科技创新2025基金项目(2022Z185) （2022Z185）
激光增材制造纳米TiC增强钼基高温合金的微结构调控和强韧化机制基金项目(52271130) （52271130）
