摘要
本文系统研究了单晶L_(12)强化富Co高熵超合金Co_(41)Ni_(35)Al_(11.5)-Ta_(2.5)Cr_(4)Ti_(6)(at%)在空气中800,900和1000℃下的氧化行为.结果表明,该合金在800至1000℃范围内均表现出优异的抗氧化性.其中,在800℃氧化后,合金表面形成了双层氧化膜,由TiO_(2)/Al_(2)O_(3)混合层和Cr_(2)O_(3)层组成.连续但不致密的Cr_(2)O_(3)层不能有效抑制内部氧化和内部氮化.在900和1000℃时形成复杂的分级结构氧化膜,主要成分为尖晶石、Cr_(2)O_(3)、TiTaO_(4)和Al_(2)O_(3).值得注意的是,在900至1000℃的温度范围内发现抗氧化性出现了反常提高.具体来说,在1000℃下形成的更复杂和连续的五层氧化层,特别是底部的连续致密的Al_(2)O_(3)层,赋予合金在1000℃下优异的抗氧化性.
The oxidation behavior of a newly developed single-crystal L_(12)-strengthened Co-rich high-entropy super-alloy,Co_(41)Ni_(35)Al_(11.5)-Ta_(2.5)Cr_(4)Ti_(6)(at%),was investigated sys-tematically in air at 800,900,and 1000℃.The results reveal that this alloy demonstrates excellent oxidation resistance from 800 to 1000℃.At 800℃,a bilayer oxide scale was formed,consisting of a TiO_(2)/Al_(2)O_(3) mixture layer and a Cr_(2)O_(3) layer.The continuous but non-dense Cr_(2)O_(3) layer could not effectively inhibit internal oxidation and internal nitridation.Complex hierarchical-structure oxide scale formed at 900 and 1000℃,mainly composed of spinels,Cr_(2)O_(3),TiTaO_(4),and Al_(2)O_(3).Surprisingly,an anomalous improvement in oxidation resistance was found in a temperature range from 900 to 1000℃.Specifically,the formation of a more complex and continuous five-layer oxide scale at 1000℃,particularly the bottom compact Al_(2)O_(3) layer,endows the alloy with excep-tional resistance to oxidation at 1000℃.
作者
肖维城
鞠江
刘少飞
肖博
周英豪
开执中
赵怡潞
杨涛
Weicheng Xiao;Jiang Ju;Shaofei Liu;Bo Xiao;Yinghao Zhou;Ji-jung Kai;Yilu Zhao;Tao Yang(Department of Materials Science and Engineering,City University of Hong Kong,Hong Kong 999077,China;Department of Mechanical Engineering,City University of Hong Kong,Hong Kong 999077,China;Hong Kong Branch of National Precious Metals Material Engineering Research Centre(NPMM),City University of Hong Kong,Hong Kong 999077,China;Center for Advanced Nuclear Safety and Sustainable Development,City University of Hong Kong,Hong Kong 999077,China;School of Materials Science and Engineering,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China;City University of Hong Kong Shenzhen Research Institute,Shenzhen 518057,China)
基金
supported by the National Natural Science Foundation of China(52222112,52101151)
Shenzhen Science and Technology Program(SGDX20210823104002016,JCYJ20220531095217039)
Hong Kong Research Grant Council(RGC,C1020-21G,C1017-21G)。
