摘要
铝锂合金作为新型液体导弹推进剂贮箱结构材料,在湿态长期贮存条件下,铝锂合金与推进剂之间相容性问题亟需解决.为此,将针对贮箱用2195铝锂合金开展应力腐蚀开裂研究,首先,采用4点弯曲法探究2195铝锂合金在30%HNO_(3)介质中的应力腐蚀性能,深入分析合金表面腐蚀形貌,重点研究由腐蚀坑处萌生的沿晶裂纹扩展行为;其次,基于实验结果运用有限元法对应力腐蚀裂纹萌生与扩展过程中的应力、应变演变过程进行了探究.结果表明:2195铝锂合金在稀硝酸中随外载挠度增大,应力腐蚀敏感性逐步降低,表面出现大面积腐蚀坑与晶间腐蚀;腐蚀程度增大到一定时,晶间强度削弱易造成晶间裂纹扩展;腐蚀裂纹扩展过程中的晶体剥落是由晶间强度和晶体变形共同决定的,其中晶间强度大小可作为衡量铝锂合金抗应力腐蚀开裂的指标.
As a new structural material of liquid missile propellant storage tank,the compatibility between Al-Li alloy and the propellant needs to be solved urgently under long-term wet storage conditions.For this reason,this paper carries out stress corrosion cracking research on 2195 Al-Li alloy for storage tanks.Firstly,four point bending method is used to investigate the stress corrosion performance of 2195 Al-Li alloy in 30%HNO_(3) medium,and conducts an in-depth analysis of the alloy surface corrosion morphology,focusing on the intergranular crack growth behavior initiated from the corrosion pit.Subsequently,based on the experimental results,the finite element method is used to explore the stress and strain evolution process during the initiation and propagation of stress corosion cracks.The results show that the stress corrosion sensitivity of 2195 Al-Li alloy gradually decreases with the increase of external load deflection in dilute nitric acid,and large corrosion pits and intergranular corrosion appear on the surface.When the degree of corrosion increases to a certain extent,the weakening of the intergranular strength can easily cause intergranular crack propagation.The crystal spalling during the corrosion crack growth is determined by the intergranular strength and crystal deformation,and the intergranular strength can be used as an index to measure the resistance of Al-Li alloy to stress corrosion cracking.
作者
朱亚峰
田干
钟建军
张炜
ZHU Yafeng;TIAN Gan;ZHONG Jianjun;ZHANG Wei(Guangzhou Institute of Science and Technology,Guangzhou 510850,China;Rocket Force University of Engineering,Xi'an 710025,China)
出处
《兵器装备工程学报》
CAS
CSCD
北大核心
2023年第8期286-292,共7页
Journal of Ordnance Equipment Engineering
基金
广东省本科高校教学质量与教学改革工程项目(粤教高函[2023]4号)
陕西省自然科学基金项目(2020JQ488)。
关键词
铝锂合金
稀硝酸
应力腐蚀
有限元
开裂
Al-Li alloy
dilute nitric acid
stress corrosion
finite element method
cracking
