摘要
高熵合金在高温下具有优异的力学性能,但在高温下抗氧化性能的不足制约了其实际工业应用。概述了高熵合金的氧化机理,包括氧化动力学规律、氧化行为以及合金元素氧化顺序规律等,归纳了高熵合金在高温下存在的问题。在此基础上,重点综述了近年来高熵合金高温抗氧化性的研究进展。其中,通过添加可生成保护性氧化物的元素可以提高高熵合金氧化层中氧化物的金属原子与其氧化物分子的体积比(Pilling-Bedworth Ratio,简称PBR),进而增强抗氧化性。但在一些特定的高熵合金中,会因其他影响氧化性的因素,降低抗氧化性。如在难熔高熵合金中加入Cr会生成Laves相进而造成晶界间的内腐蚀;含Al高熵合金中加入Ti,在氧化过程中,反而会破坏氧化物层的致密性;含有Laves相的高熵合金中添加Si,会减弱其抗氧化性。1500℃以下的高温环境中,添加超高温陶瓷或者使高熵合金陶瓷化的方法,对高熵合金抗氧化性的提升效果较好,但1500℃以上,这种高熵合金高温抗氧化性能急剧下降。最后从添加有助于生成致密氧化层的元素、引入陶瓷相、制备抗氧化涂层3个方面,对未来抗氧化性高熵合金体系的开发、性能的优化及应用进行了展望。
High entropy alloys have excellent mechanical properties at high temperatures.However,the lack of antioxidation at high temperatures restricts their practical industrial applications.The oxidation mechanism of high entropy alloys is summarized,including the law of oxidation kinetics,oxidation behavior and the order of oxidation of alloying elements.The problems of high entropy alloys at high temperatures are also induced.On this basis,the researches on antioxidation of high entropy alloys at high temperatures in recent years are mainly reviewed.Adding elements that can generate protective oxide will increase the volume ratio of the metal atoms and their oxide molecules in the oxide layer(Pilling-Bedworth Ratio,PBR),increasing the antioxidation.However,in some specific high entropy alloy systems,the antioxidation will be reduced due to other factors that affect the oxidation.For example,the addition of Cr in the refractory high entropy alloy will generate Laves phases,causing intergranular corrosion at high temperatures;adding Ti to Al-containing high-entropy alloy will destroy the density of the oxide layer during the oxidation process;the antioxidation of high entropy alloys containing Laves phases will decrease because of Si.Adding ultra-high temperature ceramics or preparing high entropy ceramics has a better effect on improving the antioxidation of high entropy alloys in high temperature environments below 1500℃.The high temperature antioxidation of high entropy alloys above 1500℃still needs to be improved.Finally,the future development,performance optimization and application of the oxidation-resistant high entropy alloy system are prospected from three aspects:adding elements that contribute to the formation of a dense oxide layer,introducing ceramic phases,and preparing antioxidant coatings.
作者
丁一
胡振峰
梁秀兵
程延海
DING Yi;HU Zhen-feng;LIANG Xiu-bing;CHENG Yan-hai(School of Mechanical Engineering,China University of Mining and Technology,Xuzhou 221116,China;National Innovation Institute of Defense Technology,Academy of Military Science PLA,Beijing 100071,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2021年第1期162-172,共11页
Surface Technology
基金
国家重点研发计划项目(2018YFC1902400)
国家自然科学基金项目(51975582)。
关键词
高熵合金
高温抗氧化性
合金元素氧化物
氧化层
超高温陶瓷
high entropy alloy
antioxidation at high temperatures
alloy element oxide
oxide layer
ultra-high temperature ceramics
