摘要
针对Mg_(97)Zn_(1)Y_(2)合金表面耐腐蚀性较差这一问题,采用近年来兴起的激光表面改性方法,同时施加超声辅助,通过观察无超声辅助和施加超声辅助的Mg-Zn-Y合金表面微观结构、元素分布和腐蚀行为等,研究超声辅助激光表面熔凝处理(laser surface melting,LSM)技术对Mg-Zn-Y合金表面耐腐蚀性的作用效果和机理。结果表明:虽然电化学测试结果证明,由于表面粗糙度的影响,LSM过程中施加超声辅助并不能显著改善样品的耐腐蚀性,但浸没腐蚀试验得出,当腐蚀时间大于8 h,S160-15、S160-20和S160-25组实验样品的腐蚀速率明显低于S160-0组实验样品;施加超声辅助激光熔凝处理的样品熔凝层厚度与超声振幅呈正相关,均高于无超声辅助激光熔凝处理的实验样品;对耐腐蚀性最好的S160-20组的样品进行电子背散射衍射分析发现,熔凝层产生分层现象,其中上部熔凝层厚度约为24.5μm,下部熔凝层厚度约为59.3μm;S160-20组样品的上部熔凝层腐蚀行为与S160-0组样品熔凝层腐蚀行为一致,但S160-20组样品的下部熔凝层出现晶粒细化现象,这些细化后的晶粒与长周期堆垛有序(long period stacked ordered,LPSO)相形成的电偶腐蚀速率低于基体晶粒与长周期堆垛有序相形成的电偶腐蚀速率。施加超声辅助会使熔凝层厚度增加,更有利于提高Mg-Zn-Y合金长期的耐腐蚀性。
In order to address the problem of poor surface corrosion resistance of Mg_(97)Zn_1Y_(2) alloy,a laser surface modification method that had emerged in recent years was adopted,and ultrasonic assistance was applied on the basis of laser surface modification treatment.The effects and mechanisms of ultrasonic-assisted laser surface melting(LSM)on the surface corrosion resistance of Mg-Zn-Y alloy were studied by observing the surface microstructure,elemental distribution,and corrosion behavior of samples with and without ultrasonic assistance.The results show that,although electrochemical test result indicates that ultrasonic assistance during LSM does not significantly improve the sample's corrosion resistance due to surface roughness effects,the immersion corrosion test reveals that when the corrosion time exceeds 8 hours,the corrosion rates of the S160-15,S160-20,and S160-25 group samples are apparently lower than that of the S160-0 group;The thicknesses of the molten layers in ultrasonic-assisted laser-melted samples are positively correlated with ultrasonic amplitude,and all of them are higher than those of the experimental samples without ultrasonic-assisted laser melting;Electron backscatter diffraction analysis of the S160-20 group samples(with the best corrosion resistance)shows a delamination phenomenon in the molten layer,with 24.5µm for the upper layer and 59.3 um for the underlying layer.The corrosion behavior of the upper molten layer in the S160-20 group samples is consistent with that in the S160-0 group samples.However,grain refinement occurs in the lower molten layer of the S160-20 group samples,and the galvanic corrosion rate formed by these refined grains and long-period stacked ordered(LPSO)phases is lower than that formed by the matrix grains and LPSO phases.Thus,the increased thickness of the molten layer induced by ultrasonic assistance is more conducive to improving the long-term corrosion resistance of Mg-Zn-Y alloy.
作者
张宏宽
高江坤
张昊泽
王梓印
许敏恒
梁鹏舟
彭珍珍
ZHANG Hongkuan;GAO Jiangkun;ZHANG Haoze;WANG Ziyin;XU Minheng;LIANG Pengzhou;PENG Zhenzhen(School of Materials Science and Engineering,Hebei University of Science and Technology,Shijiazhuang,Hebei 050018,China;Hebei Key Laboratory of Material Near-Net Forming Technology,Shijiazhuang,Hebei 050018,China)
出处
《河北科技大学学报》
北大核心
2025年第6期672-683,F0003,共13页
Journal of Hebei University of Science and Technology
基金
国家自然科学基金(52101015)。
关键词
有色金属及其合金
镁合金
激光改性
超声辅助
耐腐蚀性
non-ferrous metals and their alloys
magnesium alloy
laser modification
ultrasonic assistance
corrosion resistance
