Co对Ti45Al-8Nb-0.3Y合金组织结构和高温抗氧化性能的影响  

Effect of Co on microstructure and high temperature oxidation resistance of Ti45Al-8Nb-0.3Y alloy

作　　者：谢小青 李轩 吕威 来升 刘益 李建军 谢文玲 XIE Xiaoqing;LI Xuan;LYU Wei;LAI Sheng;LIU Yi;LI Jianjun;XIE Wenling(School of Mechanical Engineering,Sichuan University of Science and Engineering,Zigong 643000,Sichuan,China;Sichuan Aerospace Fiberhome Servo Control Technology Co.,Ltd.,Chengdu 611130,China)

机构地区：[1]四川轻化工大学机械工程学院,四川自贡643000 [2]四川航天烽火伺服控制技术有限公司,成都611130

出　　处：《材料工程》2022年第1期101-108,共8页Journal of Materials Engineering

基　　金：国家自然科学基金项目(51961003);陕西省重点研发计划(2018GY-112,2020GY-324);自贡市科技局项目(2019YGJC07,2020YGJC17);四川轻化工大学人才引进项目(2020RC19);四川省科技创新苗子工程(2021102)。

摘　　要：采用真空电弧非自耗熔炼方法制备Ti45Al-8Nb-0.3Y-m Co(m=0,0.5,1,2,原子分数/%,下同)合金,研究合金的组织和高温抗氧化性能。结果表明:Co能够明显细化TiAl-Nb合金组织,但对合金中α_(2)+γ片层组织的形成具有较强烈的抑制作用,并且会促进富Co的B_(2)相析出。Ti45Al-8Nb-0.3Y-mCo合金在1000℃空气中氧化100 h后形成的氧化膜均主要由较为疏松的TiO_(2)和Al_(2)O_(3)混合组成,且TiAl-Nb-0.3Y合金的氧化增重随Co含量增加而增大,但氧化膜的抗剥落能力随Co含量增加而明显提高;添加Co能够在一定程度上降低氧化膜的内应力,对提高其抗剥落性能有益,但引起的粗大B_(2)相析出削弱了合金的高温抗氧化性能。Ti45Al-8Nb-0.3Y-m Co(m=0,0.5,1,2,atom fraction/%)alloys were prepared by vacuum arc non-consumable melting method.The microstructure and high temperature oxidation resistance of the alloys were investigated.The results show that the microstructure of TiAl-Nb alloy can be significantly refined by addition of Co element.However,Co can remarkably inhibit the formation of α_(2)+γlamellar while promote the formation of Co-rich B_(2) precipitations in the alloys.The oxide films formed on the Ti45Al-8Nb-0.3Y-m Co alloys mainly consist of relatively loose TiO_(2) and Al_(2)O_(3) mixtures,after oxidation at 1000℃for 100 h in air.With the increase of Co content,the mass gains of the TiAl-Nb-0.3Y alloys after oxidation increase obviously,while much better anti-spalling performance of the oxide films can be obtained.Addition of Co can reduce the internal stress of the oxide film to a certain extent,which is beneficial to the anti-spalling performance of the oxide film.However,the coarse B_(2) precipitation caused by Co weakens high temperature oxidation resistance of the alloy.

关 键 词：TiAl-Nb合金 Co合金化 合金组织 高温氧化 

分 类 号：TG174.4[金属学及工艺—金属表面处理]