摘要
在等原子比的γ-TiAl基金属间化合物的基础上添加Nb、Hf、Zr元素,熔炼了3种合金,研究了这3种合金在静止空气中的1600℃高温升温过程和700℃、800℃、850℃低温下恒温20 h的氧化行为。结果表明:合金4Nb-4Zr、合金4Nb-4Hf和合金8Nb在1600℃升温氧化过程中都存在一个孕育期,温度上升至1000℃以上才开始出现急速氧化的趋势。而700℃、800℃和850℃恒温氧化过程中不存在孕育期,氧化曲线呈现抛物线型。计算和修正了三种合金分别在700℃、800℃和850℃下氧化抛物线常数K_(p)值。三种合金氧化后氧化膜主要由致密的Al_(2)O_(3)和疏松的TiO_(2)组成。合金元素主要通过影响氧化膜中致密的Al_(2)O_(3)的量来控制合金的抗氧化性。元素Hf对提高TiAl合金中Al的活度作用明显,合金氧化膜中Al_(2)O_(3)量最多,合金抗氧化性最佳。元素Nb次之,元素Zr最差。
Three kinds of alloys were melted by adding Nb,Hf and Zr elements on the basis of equal atomic ratioγ-TiAl based intermetallic compounds.The oxidation behavior of the three alloys in still air at 1600℃and at 700℃,800℃and 850℃for 20 h was studied.The results show that there is an incubation period in the oxidation process of 4Nb-4Zr,4Nb-4Hf and 8Nb at 1600℃,and the rapid oxidation begins when the temperature rises above 1000℃.However,there is no incubation period in the isothermal oxidation process at 700℃,800℃and 850℃,and the oxidation curve is parabolic.The parabolic constants K_(p) of the three alloys at 700℃,800℃and 850℃were calculated and corrected.The oxide films of the three alloys are mainly composed of dense Al_(2)O_(3) and loose TiO_(2).Alloying elements control the oxidation resistance of the alloy mainly by affecting the amount of dense Al_(2)O_(3) in the oxide film.Hf plays an important role in improving the activity of Al in TiAl alloy.The amount of Al_(2)O_(3) in the oxide film is the most,and the oxidation resistance of the alloy is the best.Nb is the second,Zr is the worst.
作者
赖旭平
李天方
刘瑞
孙红亮
LAI Xuping;LI Tianfang;LIU Rui;SUN Hongliang(Naval Equipment Department,Chengdu 610036,China;School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第S01期374-377,共4页
Materials Reports
基金
国家重点研发计划(2016YFB1200505)。
