电火花沉积修复铝合金组织与可降解性能  

Microstructure and Degradability of Aluminum Alloy Repaired by Electro-spark Deposition

作　　者：张建斌[1,2] 张雷雷 刘航 容煜 焦凯 石玗[1,2] ZHANG Jian-bin;ZHANG Lei-lei;LIU Hang;RONG Yu;JIAO Kai;SHI Yu(State Key Laboratory of Advanced Processing and Reuse of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Non-ferrous Metals Alloys and Processing of the Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,China;Lanzhou Jinchuan Technology Park Co.,Ltd,Lanzhou 730010,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州理工大学有色金属合金及加工教育部重点实验室,兰州730050 [3]兰州金川科技园有限公司,兰州730010

出　　处：《表面技术》2020年第10期224-232,共9页Surface Technology

基　　金：国家自然科学基金青年项目(51805234);甘肃省引导科技创新发展专项资金项目(2019ZX-08);甘肃省基础研究创新群体计划(17JR5RA107)。

摘　　要：目的采用电火花沉积技术修复铝合金铸造缺陷。方法采用两种电极(ER5356电极和自制电极),在优化电火花沉积工艺条件下,修复铝合金表面气孔,系统研究电火花沉积工艺、电极材料、沉积气氛对修复层的影响。采用扫描电子显微镜(SEM)结合能谱仪(EDS)对修复层界面组织和成分进行表征;用显微硬度计测试修复层的硬度;用电化学工作站测试修复层的Tafel曲线,在水浴中测试修复层的降解速率,从热力学与动力学两方面对修复层的降解性能进行全面评价。结果在氩气气氛中的最佳修复工艺参数为:频率5000 Hz,电容150μF,沉积角度45°,此时的热输入为0.480 J。在氩气气氛中的修复层组织致密,且元素均匀分布,减小了成分偏析。由于消除了枝晶,修复层的硬度相对于基体的硬度略有提高。自制电极修复层的自腐蚀电位(–1.493 V)低于基体的自腐蚀电位(–1.421 V),ER5356电极修复层不溶于水,自制电极修复层降解速率稍快于基体。结论使用电火花沉积技术,可对3.5英寸压裂球表面缺陷进行修复,经测试,硬度和降解性能达到工程指标。The work aims to repair the defect of aluminum alloy casting by electro-spark deposition(ESD)technology.Two kinds of electrodes(ER5356 electrode and self-manufactured electrode)were used to repair the pores on the surface of aluminum alloy under the optimized electro-spark deposition conditions.The effects of ESD process,electrode materials,and deposition atmosphere on the repair layer were systematically studied.Scanning electron microscope(SEM)and energy dispersive spectrometer(EDS)were used to characterize the microstructure and element distribution of the repair layer interface.The microhardness of repair layer was tested by microhardness meter.The Tafel curve of repair layer was tested with electrochemical workstation,and the degradation rate was tested in water bath.The degradability of the repair layer was comprehensively evaluated from the aspects of thermodynamics and kinetics.Under the protective atmosphere of argon gas,the optimal repair process parameters were frequency of 5000 Hz,capacitance of 150μF,and deposition angle of 45°,and the heat input at this time was 0.480 J.The repair layer had a dense structure and uniform element distribution,and the component segregation was small.The microhardness of the repair layer was higher than that of the substrate due to the elimination of dendrites.The self-corrosion potential of the repaired sample(–1.493 V)was lower than that of the substrate(–1.421 V).The degradation rate of the self-manufactured electrode repaired layer was slightly faster than that of the substrate due to that the ER5356 electrode repair layer was insoluble in water.The surface defects of 3.5 inches aluminum alloy fracturing balls can be repaired by ESD technology,and the results show that the microhardness and degradability reach engineering targets.

关 键 词：电火花沉积 修复 铝合金 组织 降解性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG245[金属学及工艺—金属学]