激光选区熔化AlMgScZr合金微观组织与电化学腐蚀性能研究  

Microstructure and Electrochemical Corrosion Properties of AlMgScZr Alloys Fabricated Using Selective Laser Melting

作　　者：邹田春 梅思远 陈敏英 Zou Tianchun;Mei Siyuan;Chen Minying(College of Safety Science and Engineering,Civil Aviation University of China,Tianjin 300300,China)

机构地区：[1]中国民航大学安全科学与工程学院,天津300300

出　　处：《中国激光》2023年第4期85-94,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(52071069)。

摘　　要：采用激光选区熔化(SLM)技术成形了AlMgScZr合金,分析了不同扫描速度下制备的合金的微观组织及其在质量分数为3.5%的NaCl溶液中的动电位极化曲线和电化学阻抗谱,研究了SLM成形AlMgScZr合金的微观组织对其电化学腐蚀性能的影响。结果表明,在质量分数为3.5%的NaCl溶液中,SLM成形的AlMgScZr合金表现出明显的钝化行为。合金中的孔隙降低了表面钝化膜的稳定性,从而降低了合金的抗电化学腐蚀性能。由于熔池边界处高数量密度的Al3(Sc,Zr)颗粒可以作为微阴极促进Al基体的溶解,熔池边界发生了严重的腐蚀。此外,随着扫描速度的增大,AlMgScZr合金的晶粒尺寸逐渐减小、小角度晶界逐渐增多。晶粒尺寸的减小导致晶界密度和晶界处的活性原子数量逐渐增多,提高了钝化膜的生长速度,同时,小角度晶界的增多提高了晶界的稳定性,从而改善了合金的抗电化学腐蚀性能。Objective AlMgScZr alloys fabricated using selective laser melting(SLM)technology have promising applications in the designing and manufacturing of aircrafts due to their superior mechanical properties.However,during the service of the aircraft,the aluminum-alloy structure encounters severe corrosion issues,particularly in coastal and wet environments.Corrosion in aircraft structures poses a significant risk to flight safety;therefore,the materials used in an aircraft must undergo a stringent review to determine if their performance meets the requirements of airworthiness regulations.Presently,domestic and international researchers have focused primarily on the mechanical properties of SLM-fabricated AlMgScZr alloys,with less attention on corrosion resistance.In the previous study,we successfully prepared an Al-4.8Mg-0.82Sc-0.28Zr alloy using SLM;the ultimate tensile strength and elongation attained 344.20 MPa and 24.5%,respectively.Considering the severity of corrosion,we investigated the electrochemical corrosion(the most common type of corrosion observed in aircrafts)properties of SLM-fabricated AlMgScZr alloys and discussed the effect of the microstructure of these alloys on their electrochemical corrosion performance.We anticipate that our research will serve as a resource for the industrial application of the AlMgScZr alloys formed using SLM.Methods The AlMgScZr alloy was prepared using SLM at different scanning speeds(800,1000,1200,1400,and 1600 mm/s).Initially,the relative densities of various specimens were measured,and the types and distributions of defects in the alloys were characterized via optical microscopy(OM)and scanning electron microscopy(SEM).Subsequently,the microscopic morphology,precipitation phases,and grain information of the alloy were studied using transmission electron microscopy(TEM)and electron backscatter diffraction(EBSD),and the effect of scanning speed on the microstructure of the alloy was analyzed.The electrochemical corrosion performance of the specimens was then evaluated usi

关 键 词：激光技术 激光选区熔化 AlMgScZr合金 微观组织 电化学腐蚀性能 

分 类 号：TG113.231[金属学及工艺—物理冶金]