30%HNO_(3)对2195铝锂合金预腐蚀疲劳特性研究  

Research on pre-corrosion fatigue properties of 2195 Al-Li alloys in 30%HNO_(3)

作　　者：刘德俊 田干 李玉龙 张炜 张有宏 LIU Dejun;TIAN Gan;LI Yulong;ZHANG Wei;ZHANG Youhong(School of Missile Engineering,Rocket Force University of Engineering,Xi’an 710025,China;China Academy of Launch Vehicle Technology,Beijing 100076,China)

机构地区：[1]火箭军工程大学导弹工程学院,西安710025 [2]中国运载火箭技术研究院,北京100076

出　　处：《北京航空航天大学学报》2024年第4期1129-1137,共9页Journal of Beijing University of Aeronautics and Astronautics

基　　金：国家自然科学基金(52272446,52075541);陕西省自然科学基金(2022JM-243)。

摘　　要：模拟液体导弹贮箱材料和使用特点,进行2195-T8铝锂合金在30%硝酸溶液中预腐蚀不同时间后的疲劳试验,利用扫描电子显微镜(SEM)、电子背散射衍射仪(EBSD)及透射电子显微镜(TEM)等显微表征方法,研究了预腐蚀对疲劳性能的影响。结果表明:预腐蚀表面形貌以晶间腐蚀和点蚀为主,在轧制方向上形成条带状腐蚀链,其产生与长条形晶界和金属间粒子连续腐蚀作用相关;经预腐蚀后,铝锂合金试样在210,280,330 MPa中等应力幅下的预腐蚀疲劳寿命较无腐蚀试样有所增加,16 h腐蚀试样寿命提高最为明显,其原因是腐蚀通过将合金表面微裂纹、孔洞等缺陷消除、增加表面粗糙度等方式,降低了应力集中程度,进而延缓了疲劳裂纹萌生。To simulate the material and application characteristics of liquid-missile propellant tanks,fatigue tests were carried out after pre-corrosion in 30%HNO3 for different hours.Effects of pre-corrosion on fatigue properties were investigated by scanning electron microscopy(SEM),transmission electron microscope(TEM),and electron backscatter detector(EBSD)methods.The results show that the surface morphology after corrosion is mainly composed of intergranular corrosion and pitting.Stripped corrosion chains are produced along the rolling direction,which are related with corroded long grain boundaries and intermetallic particles.The fatigue limit values of precorroded specimens are lower than those of the uncorroded specimens.The fatigue limit of 16 h corroded specimens is the highest,while the limit of 24 h corroded specimens declines to zero.The fatigue cycles under median stress amplitudes of 210 MPa,280 MPa and 330 MPa,higher than those of uncorroded specimens,and the increase of 16 h corroded specimens is the most obvious.The enhancement of fatigue cycles attributes to the elimination of microcracks,pores and the improvement of surface roughness through pre-corrosion,which reduces the stress concentration and retards the crack initiation.

关 键 词：铝锂合金 推进剂贮箱 预腐蚀 疲劳特性 裂纹萌生 

分 类 号：V45[一般工业技术—材料科学与工程] TG178[金属学及工艺—金属表面处理]