Ti_2AlNb合金在不同温度下的热盐腐蚀行为  

Hot salt corrosion behavior of Ti2AlNb alloys at different temperatures

作　　者：孙光耀 刘石双 周毅 曹京霞 黄旭 SUN Guangyao;LIU Shishuang;ZHOU Yi;CAO Jingxia;HUANG Xu(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;AECC Key Laboratory on Advanced Titanium Alloys,Beijing 100095,China)

机构地区：[1]中国航发北京航空材料研究院,北京100095 [2]中国航发先进钛合金重点实验室,北京100095

出　　处：《材料工程》2024年第8期159-168,共10页Journal of Materials Engineering

摘　　要：为提高Ti_2AlNb合金作为航空发动机部件在海洋环境下服役的可靠性,研究名义成分为Ti-22Al-23Nb-1Mo-1Zr(原子分数/%)的Ti_(2)AlNb合金在550,650,750℃时涂盐Na_(2)SO_(4)/NaCl(95/5,质量比)的热腐蚀行为,绘制不同温度下合金的腐蚀增重曲线,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)对热盐腐蚀后合金的表面形貌、截面结构以及腐蚀产物进行观察分析。结果表明:550℃时合金腐蚀速率较低,表面氧化层平直、致密且完整,表现出优异的抗热盐腐蚀能力;650℃时合金腐蚀增重曲线符合抛物线规律,氧化层表面发生小范围的剥落,内部出现裂缝且有轻微的分层现象,合金整体上表现出良好的抗热盐腐蚀能力;750℃时合金腐蚀过程中出现明显减重,氧化层表面严重开裂剥落,内部出现明显的层状结构,由两种腐蚀产物层交替叠加:其中主要腐蚀产物层以TiO_(2)为主并含有NbAlO_4等多种腐蚀产物,另一层以NaNbO_(3)为主,合金的抗热盐腐蚀能力严重下降。To enhance the reliability of Ti2AlNb alloys as an aerospace engine component in marine environments,the hot salt corrosion behavior of Ti_(2)AlNb alloy with nominal compositions of Ti-22Al-23Nb-1Mo-1Zr(atom fraction/%)coated with Na_(2)SO_(4)/NaCl(95/5,mass ratio)at temperatures of 550,650℃and 750℃was investigated.The corrosion mass gain curves of alloys at different temperatures were drawn.The surface morphologies,cross-section structures,and corrosion products of the alloy after hot salt corrosion were examined and analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive X-ray spectroscopy(EDS).The results show that the corrosion rate at 550℃is lower and the oxide scales are straight,dense and intact,exhibiting excellent resistance to hot salt corrosion.The corrosion mass gain curves of the alloy follow a parabolic law at 650℃and the oxide scales exhibit small-scale peeling and internal cracks,with a slightly layered structure.The alloy exhibits good resistance to hot salt corrosion at 650℃in general.A significant mass loss is observed during the corrosion process at 750℃,with the oxide scales cracking and peeling severely.Furthermore,within the oxide scales emerges a distinct layered structure where two layers of corrosion products alternately exist:the main layer is mainly composed of TiO2 and contains various corrosion products including NbAlO4,while the other layer is mainly composed of NaNbO_(3).The resistance to hot salt corrosion of the alloy decreases seriously at 750℃.

关 键 词：Ti_2AlNb合金 热盐腐蚀 混合盐 温度相关 

分 类 号：TG172.62[金属学及工艺—金属表面处理] TB31[金属学及工艺—金属学]