铝合金表面激光沉积Al0.8FeCoNiCrCux高熵合金组织与耐蚀性能

为增强5XXX系铝合金表面的耐蚀性能,利用脉冲激光沉积技术制备了Al0.8FeCoNiCrCux高熵合金(HEA)涂层。利用XRD,SEM和电化学工作站分析了Al0.8FeCoNiCrCux高熵合金的相结构、微观组织和耐腐蚀性能。结果表明随着Cu含量增加,合金的相结构由BCC1和BCC2相转变为BCC1,BCC2和FCC相;当=0时,Al0.8FeCoNiCrCux涂层沿晶间出现裂纹,x=0.25时,涂层裂纹消失,并且在晶间出现了浅色组织,随着x增加,浅色组织由点状分布转变为连续生长;Al0.8FeCoNiCrCux(x=0.25,0.5,0.75,1.0)高熵合金涂层耐蚀性随Cu增加而降低,Al0.8FeCoNiCrCu0.25的腐蚀电流密为7.94×10^-8 A/cm^2,仅为基材的0.17%,腐蚀形式为点蚀,当x增加至1时,腐蚀电流密度增至8.21×10^-7 A/cm^2,为基材的1.99%,腐蚀形式转变为晶间腐蚀,但仍优于基材。显然,当0.25≤x≤1时,采用Al0.8FeCoNiCrCux涂层可显著改善铝合金的耐腐蚀性能。同时,其具有的高熵效应可抑制涂层中由基材的稀释行为引起的金属间化合物形成,解决了传统涂层材料应用在铝合金表面易产生裂纹的问题。

Microstructure and crossion resistance of laser deposition of Al0.8FeCoNiCrCux high-entropy alloy on aluminum alloy

To improve thecorrosion resistance of the 5xxx aluminum alloy surface,Al0.8FeCoNiCrCux(x=0,0.25,0.5,0.75,1.0)coatings were prepared on the surface of the alloy vialaser deposition.The crystal texture,micro-structure,andcorrosion resistance of the deposition were analyzed via XRD,SEM and electrochemical workstations.The results demonstrate that with the increase in the quantity of Cu,the phase structure of the HEA changes from BCC1 and BCC2 to BCC1,BCC2,and FCC.Furthermore,when x=0,cracks appeared in the Al0.8FeCoNiCrCux coating,and when x=0.25,the cracks disappeared,and a light structure was observed in the interdendritic region.With the increase inx,the light structure changed from point distribution to continuous growth.The corrosion resistance of the alloy increased with the decrease in the quantity of Cu,the corrosion current density of Al0.8FeCoNiCrCu0.25 high entropy-alloy coating was estimated to be 7.94×10^-8 A/cm^2,and the form of corrosion was ascertained to bepitting.Additionally,the corrosion current density of Al0.8FeCoNiCrCuhigh entropy-alloy coating was ascertained to be 8.21×10^-7 A/cm^2.It also exhibited obvious intercrystalline corrosion,but was still superior to the substrate.This demonstrates that Al0.8FeCoNiCrCuxHEA(0.25≤x≤1)can be used as a coating to enhance the corrosion resistance of aluminum,and its high entropy effect can simultaneously inhibit the formation of inter-metallic compounds caused by the dilution of the substrate.This therefore addresses the problem of crack formation in coatings prepared with traditional materials.