Hot Corrosion Behavior of TiAl and TiAl-9Nb Alloys in Molten Salt Environment

被引：0
|
作者：
Li Y. [1 ]
Geng G. [1 ]
Li N. [1 ]
Dong F. [1 ]
Hou J. [1 ]
机构：
[1] School of Material Science & Engineering, Beifang University of Nationalities, Yinchuan
来源：
Xiyou Jinshu/Chinese Journal of Rare Metals | 2019年 / 43卷 / 06期
关键词：
Hot corrosion; Molten salts; TiAl alloy; TiAl-9Nb alloy;
D O I：
10.13373/j.cnki.cjrm.XY18060006
中图分类号：
学科分类号：
摘要：
Hot corrosion behavior of TiAl and TiAl-9Nb alloys in molten salt environment of 25%NaCl+75%Na2SO4 (mass fraction) at 850℃ was investigated. Scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS) and X-ray diffractometer (XRD) were employed to investigate the surface morphologies, microstructures and phase constitutions of the corrosion films. The results show that the corrosion products of both TiAl and TiAl-9Nb alloys were mainly composed of TiO2, Al2O3 and a small amount of TiS. The corrosion film was loose and easy to peel off, and thus had little protective effects to the substrate. During hot corrosion, NaCl broke the protective scales formed on TiAl and TiAl-9Nb alloys by producing corrosive Cl2, and then, selective corrosion characterized by internal oxidation and internal sulfide occurred along the α2 phase in TiAl and β phase in TiAl-9Nb. The higher concentration of Al in β phase in TiAl-9Nb alloy than that of α2 phase in TiAl alloy, as well as the structural differences between the two phases should be the main reasons responsible for the better hot corrosion resistance of TiAl-9Nb than TiAl. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.
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页码：571 / 576
页数：5
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