选区激光熔化Ti-6Al-4V合金微观组织与腐蚀行为  

Microstructure and corrosion behavior of Ti-6Al-4V alloy using selective laser melting

作　　者：王怀慎 陈磊 张红霞[1] 柴斐 闫晓英 董鹏 WANG Huaishen;CHEN Lei;ZHANG Hongxia;CHAI Fei;YAN Xiaoying;DONG Peng(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan,030024,China;CSSC Fenxi Heavy Industry Co.,Ltd.,Taiyuan,030027,China)

机构地区：[1]太原理工大学,材料科学与工程学院,太原030024 [2]中国船舶集团汾西重工有限责任公司,太原030027

出　　处：《焊接学报》2025年第4期125-132,共8页Transactions of The China Welding Institution

基　　金：山西省重点研发计划(202102150401003)。

摘　　要：为了揭示选区激光熔化(selective laser melting,SLM)在钛合金水下装备触水部件上的应用可行性,文中对SLM制备的Ti64合金在模拟海水环境下的耐腐蚀性能进行了研究.结果表明,SLM制备Ti64合金主要以针状α'马氏体组织为主,β相的含量约为0.3%.对比电化学测试发现,在质量分数为3.5%的NaCl溶液中,SLM制备Ti64合金的开路电位E_(ocp)为−119.3 mV,远低于与锻造Ti64合金的234.12 mV.采用外推法分析动电位极化曲线,SLM制备Ti64合金的腐蚀电位E_(corr)为−237.3 mV,同样低于锻造Ti64合金的118.4 mV;采用等效电路对阻抗谱进行拟合分析,SLM制备Ti64合金钝化膜电阻Rf和电荷转移电阻Rct分别为184.1 kΩ·cm^(2)和2.76×10^(5)MΩ·cm^(2),均低于锻造Ti64合金,钝化膜电阻Rf和电荷转移电阻Rct分别为231 kΩ·cm^(2)和4.26×10^(5)MΩ·cm^(2).通过对不同应变速率下的慢应变应力腐蚀结果进行分析,在应变速率为1×10^(−5)s^(−1),5×10^(−5)s^(−1)和1×10^(−6)s^(−1)下,SLM制备Ti64合金的应力腐蚀敏感性分别为20.2%,17.2%和14.4%,均高于同等条件锻造Ti64合金的−1.4%,12.9%和10.8%.To reveal the feasibility of applying selective laser melting(SLM)to titanium alloy-made underwater equipment components,the corrosion resistance of SLM-prepared Ti64 alloy in a simulated seawater environment was explored.The research finds that the SLM-prepared Ti64 alloy primarily consists of needle-likeα'martensite,with aβ-phase content of approximately 0.3%.Comparison through electrochemical tests reveals that in a NaCl solution with a mass fraction of 3.5%,the open-circuit potential of SLM-prepared Ti64 is^(−1)19.3 mV,significantly lower than that of wrought Ti64(234.12 mV).The analysis of the potentiodynamic polarization curves using the extrapolation method shows that the corrosion potential(E_(corr))of the SLM-prepared Ti64 is−237.3 mV,also lower than that of wrought Ti64(118.4 mV).By fitting the impedance spectra with an equivalent circuit model,the passive film resistance(Rf)and charge transfer resistance(Rct)of the SLM-prepared Ti64 alloy are 192.4 kΩ·cm^(2)and 2.69 MΩ·cm^(2),respectively,both lower than those of wrought Ti64(235 kΩ·cm^(2)and 4.34 MΩ·cm^(2)).The slow stress and strain corrosion results at different strain rates are analyzed.At strain rates of 10^(−5)s^(−1),5×10–6 s^(−1),and 10–6 s^(−1),the stress corrosion susceptibility of the SLM-prepared Ti64 alloy is 20.2%,17.2%,and 14.4%,respectively,all higher than that of wrought Ti64 under the same conditions(−1.4%,12.9%,and 10.8%).

关 键 词：激光选区熔化 Ti-6AI-4V合金 微观组织 耐腐蚀性能 

分 类 号：TG456.7[金属学及工艺—焊接]