高低温交替海洋环境Ti6Al4V合金的腐蚀损伤机理  

Corrosion Damage Mechanism of Ti6Al4V Alloy in AlternatingHigh and Low Temperature Marine Environment

作　　者：陈伟[1] 胡素影[1] 向林 高旭[1] 陶健全[2] 陈永君 孙际鹏 解志文[1] CHEN Wei;HU Su-ying;XIANG Lin;GAO Xu;TAO Jian-quan;CHEN Yong-jun;SUN Ji-peng;XIE Zhi-wen(University of Science and Technology Liaoning,Liaoning Anshan 114051,China;Southwest Institute of Technology and Engineering,Chongqing 400039,China)

机构地区：[1]辽宁科技大学,辽宁鞍山114051 [2]西南技术工程研究所,重庆400039

出　　处：《表面技术》2023年第8期237-246,共10页Surface Technology

基　　金：西南技术工程研究所合作基金(HDHDW5902020103)。

摘　　要：目的探究高低温交替海洋服役环境中Ti6Al4V合金的腐蚀损伤失效过程,揭示高温氧化、沉积盐膜、频繁启动工作模式耦合作用下合金的腐蚀损伤与退化机理。方法采用高温氧化、高温氧化-盐雾交替和高温氧化-海水浸泡交替试验方法,对Ti6Al4V合金腐蚀失效行为进行了全面评估;利用X-射线衍射仪(XRD)、X-射线光电子能谱仪(XPS)与扫描电子显微镜(SEM)等微尺度检测分析仪器,全面解析了合金损伤失效过程中表面物相结构、腐蚀产物成分及表/截面形貌特征。结果650℃氧化400 h后,Ti6Al4V合金表面氧化层(TiO_(2)+Al_(2)O_(3))生长致密且均匀;经50循环高温氧化-盐雾交替试验后,Ti6Al4V合金遭受加速腐蚀损伤,表面存在明显点蚀,氧化层出现分层剥落;经50循环高温氧化-海水浸泡试验后,Ti6Al4V合金腐蚀损伤进一步加速,但氧化层生长迅速,整体增重达5.167 mg/cm^(2)。结论高温氧化过程中Ti6Al4V合金表面氧化层呈缓慢均匀生长特征,具有优良的抗氧化性。高低温交替工作模式加速了氧化膜快速生长与结构破坏,Cl^(-)的浓度对Ti6Al4V合金表面氧化层的降解具有显著驱动作用,且Cl^(-)浓度越高腐蚀降解越严重。随着样品表面氧化层的致密性和完整性被破坏,混合盐逐渐侵入氧化层内部,加剧了氯化物的挥发,表明Ti6Al4V合金在高低温交替环境下抗腐蚀性较差。The frequent alternating high and low temperature service pattern of aero engines in the marine environment is an important factor that reduces their service life.The work aims to investigate the corrosion damage failure process of Ti6Al4V alloy in alternating high and low temperature marine service environment and reveal in detail the corrosion damage and degradation mechanisms of the alloy under the synergistic effects of high temperature oxidation,deposited salt films and frequent start-up operating modes.High temperature oxidation,alternating high temperature oxidation-salt spray and alternating high temperature oxidation-seawater immersion tests were employed to evaluate the corrosion behaviors of Ti6Al4V alloy.The phase composition of the test sample surface was characterized by X-ray diffractometry(XRD).The microstructure and local elemental distribution of the test samples were characterized by scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS).Corrosion product composition and compound valence were characterized by X-ray photoelectron spectroscopy(XPS).An in-suit dense and uniform(TiO_(2)+Al_(2)O_(3))oxide layer was formed on the surface of Ti6Al4V alloy after oxidation at 650℃for 400 h.The rate of sample weight gain gradually decreased over time during the test and was only 2.657 mg/cm^(2)at the end of the test.Ti6Al4V alloy showed significant cracking and peeling on the surface of the sample after 50 cycles of alternating high temperature oxidation and salt spray test.Severe corrosion damage occurred on the alloy surface caused by the transformation of the liquid salt film in the salt spray environment into a solid salt film adhered to the sample surface in the high temperature environment,which resulted in the laminar separation of the oxide layer.Corrosion damage to the Ti6Al4V alloy was further accelerated during 50 cycles of high temperature oxidation-seawater immersion test,reflected by a rapid growth of the oxide film and an aggravated delamination failure.Although corrosi

关 键 词：TI6AL4V合金 海洋环境 高温氧化 高温氧化-盐雾交替 高温氧化-浸泡交替 腐蚀损伤机理 

分 类 号：TG172[金属学及工艺—金属表面处理]