搅拌摩擦加工制备Al6061/SiC复合材料的耐蚀性研究  

Investigation on Corrosion Resistance of Al6061/SiC Composite Prepared with Friction Stir Processing

作　　者：张翠翠[1] 吴化[2] 于晓丰 ZHANG Cui-cui;WU Hua;YU Xiao-feng(Changchun Guanghua University,Changchun 130033,China;Key Laboratory of Advanced Structural Materials of Ministry of Education,Changchun University of Technology,Changchun 130012,China)

机构地区：[1]长春光华学院,长春130033 [2]长春工业大学先进结构材料教育部重点实验室,长春130012

出　　处：《表面技术》2021年第5期315-320,共6页Surface Technology

摘　　要：目的利用搅拌摩擦加工技术制备纳米SiC铝基复合材料,研究经过纳米粒子的添加和FSP作用后,其耐腐蚀性能的变化及原因。方法室温条件下,在3.5%NaCl溶液中,通过电化学阻抗谱和动电位极化曲线对试样的耐腐蚀性能进行检测分析。利用电子背散射衍射技术和透射电镜对3种试样的显微组织进行表征,研究耐腐蚀性能的变化机理。结果经搅拌摩擦加工后,样品的阻抗值明显提高,动电位极化曲线测试结果显示,母材、FSP试样和复合材料试样的自腐蚀电位分别为–1.517、–1.338、–1.339V,而腐蚀电流密度分别为0.48、0.11、0.12 m A/cm^(2)。FSP加工试样的晶粒由平均晶粒尺寸为8.7μm左右的等轴晶粒构成,并且大部分析出相因高温作用发生溶解,而纳米SiC粒子的加入,使晶粒尺寸进一步降低至4.1μm左右。结论所制备Al6061/SiC复合材料的耐腐蚀性能相较于母材明显改善,但弱于FSP试样。SiC和基体之间电位差的存在构成腐蚀微电池,降低材料的耐腐蚀性能,而晶界数量的增加造成点阵空位等缺陷增加,导致电荷转移的阻力增加,耐腐蚀性能得到改善。Al/nano-SiC composite was fabricated to investigate the effect of the additional nano-particulate on corrosion resistance and its mechanism by friction stir processing.Corrosion resistance of specimens was detected through electrochemical impedance spectroscopy and potentiodynamic polarization techniques in 3.5%NaCl solution at room temperature.Electron back-scattered diffraction and transmission electron microscopy were employed for thorough microstructural characterization to investigate the corrosion resistance variation mechanism of three specimens.After FSP,the specimens impedance increased significantly,and the corrosion potential for base metal,FSP sample and composite were–1.517,–1.338 and–1.339 V and the corrosion current density for them are 0.48,0.11 and 0.12 mA/cm^(2),respectively.The grain structure of specimens fabricated by friction stir processing was composed of isometric crystal grain with an average grain size of about 8.7μm,and most of the precipitates dissolved due to high temperature.However,the addition of nano SiC particles further reduced the grain size to about 4.1μm.The corrosion resistance of Al6061/nano-SiC composite is higher than base metal,but weaker than FSP sample.The difference between SiC and matrix forms the corrosive cell,which has a negative effect on corrosion resistance.The increase of the number of grain boundaries leads to the increase of lattice vacancy and other defects,which results in the increase of charge transfer resistance to improve the corrosion resistance.

关 键 词：FSP加工 Al6061/SiC 耐腐蚀性能 晶粒细化 点阵空位 

分 类 号：TG174.4[金属学及工艺—金属表面处理]