DZ445镍基高温合金高温长时间氧化形成的多层膜结构  

Multilayer Structure of DZ445 Ni-Based Superalloy Formed by Long Time Oxidation at High Temperature

作　　者：刘来娣 丁彪 任维丽[1,2] 钟云波 王晖[3] 王秋良 LIU Laidi;DING Biao;REN Weili;ZHONG Yunbo;WANG Hui;WANG Qiuliang(State Key Laboratory of Advanced Special Steel,School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China;Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University,Shanghai 200444,China;Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]上海大学材料科学与工程学院省部共建高品质特殊钢冶金与制备国家重点实验室,上海200444 [2]上海大学上海市钢铁冶金新技术开发应用重点实验室,上海200444 [3]中国科学院电工研究所,北京100190

出　　处：《金属学报》2023年第3期387-398,共12页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51871142;省部共建高品质特殊钢冶金与制备国家重点实验室、上海市钢铁冶金新技术开发应用重点实验室自主研发项目No.SKLASS2020-Z04;上海市科学技术委员会项目No.19DZ2270200。

摘　　要：研究了高Cr/Al比和中Ta含量的DZ445镍基高温合金在900℃下300~2600 h的氧化行为。结果表明,900℃氧化≥500 h,氧化膜呈现多层结构,最外层氧化物相为NiCr_(2)O_(4)、Cr_(2)O_(3)和TiO_(2),次外层为CrTaO_(4)和TiO_(2),次内层为Al_(2)O_(3)、NiCr_(2)O_(4)和NiO,最内层主要是Al_(2)O_(3)。次外层和次内层的出现使得合金氧化速率降低,表现为动力学方程的指数大幅度增加和氧化速率常数急剧下降。这2层的出现也使得合金氧化机理发生转变,次外层形成后氧化过程由合金元素Cr、Ti、Ni向外扩散转变为由Al的向外扩散和O的向内扩散所控制;次内层形成后,氧化过程转变为Ni、Cr的向外扩散和O的向内扩散所控制。这种多层氧化膜结构使得DZ445合金表现出优异的抗氧化能力。Nickel-based superalloys have been widely used in aero engines and gas turbines because of their excellent high-temperature strength and exceptional oxidation resistance.The oxidation resistance is obtained using the thermal barrier coatings and alloying elements.In the previous investigations,the oxidation time of the nickel-based superalloys has been focused on hundreds of hours.However,in practice,the superalloys last far longer.This study investigated the superalloy DZ445’s oxidation behavior at 900℃for 300-2600 h.An oxidation film with a four-layer structure is formed after oxidation at900℃for 500 h and above.The outermost layer is primarily composed of NiCr_(2)O_(4),Cr_(2)O_(3),and TiO_(2).The subouter layer consists of CrTaO_(4)and TiO_(2),and the subinner layer consists of Al_(2)O_(3),NiCr_(2)O_(4),and NiO.The innermost layer is primarily Al_(2)O_(3).The appearances of the subouter layer and subinner layer greatly reduce the oxidation rate of the alloy,which is represented by the dramatic increase in the oxidation kinetics equation exponent and a sharp reduction of the oxidation rate constant.The formation of subouter layer changes the oxidation mechanism from outward diffusion of alloy elements to O-inward diffusion.When the subinner layer is formed,the oxidation behavior is controlled using the outward diffusion of Ni and Cr and the O-inward diffusion.The multilayer structure gave the alloy an excellent oxidation resistance capacity.

关 键 词：镍基高温合金 氧化 多层结构氧化膜 

分 类 号：TG132.3[一般工业技术—材料科学与工程]