FeCoNiCrNb_(0.5)Mo_(0.25)高熵合金激光熔覆层组织的共晶化行为及耐磨耐蚀机理  

Eutectic Behavior and Wear and Corrosion Resistance Mechanisms of FeCoNiCrNb_(0.5)Mo_(0.25) High-Entropy Alloy Laser Cladding Layer Microstructure

作　　者：周子钧 姜芙林 杨发展 王玉玲 杨勇 宋鹏芳 仲照琳 Zhou Zijun;Jiang Fulin;Yang Fazhan;Wang Yuling;Yang Yong;Song Pengfang;Zhong Zhaolin(Key Laboratory of Laser Green Intelligent Manufacturing Technology,School of Mechanical and Automotive Engineering,Qingdao University of Technology,Qingdao 266520,Shandong,China)

机构地区：[1]青岛理工大学机械与汽车工程学院激光绿色智能制造技术重点实验室,山东青岛266520

出　　处：《中国激光》2023年第4期104-119,共16页Chinese Journal of Lasers

基　　金：山东省重点研发计划(2019GNC106102);山东省自然科学基金(ZR2019MEE059,ZR2021ME198)。

摘　　要：针对42CrMo材质舰船艉轴等海工装备在高盐、潮湿、重载环境下的表面腐蚀、磨损问题,本团队利用激光熔覆技术在42CrMo基体表面制备FeCoNiCrNb_(0.5)Mo_(0.25)高熵合金熔覆层,探究了FeCoNiCrNb_(0.5)Mo_(0.25)高熵合金激光熔覆层在不同激光功率下的组织共晶化及其对耐磨性与耐蚀性的强化机理。研究结果表明:FeCoNiCrNb_(0.5)Mo_(0.25)高熵合金激光熔覆层呈现由FCC相和Laves相组成的不完全共晶组织形态;适当提高激光功率可以促进组织的共晶化,特别是当激光功率为1400 W时,高熵合金熔覆层中部呈现为层状间距约为86 nm的纳米共晶组织;过高的激光功率导致基体中的Fe元素对高熵合金熔覆层的稀释作用增强,减弱了Mo和Nb对组织共晶化的促进作用;激光熔覆功率的增加会增强基体元素对熔覆层的稀释作用,降低熔覆层的平均硬度,当激光熔覆功率为1200 W时熔覆层具有最高的显微硬度665.8 HV1.0(约为基体的2.34倍);与基体相比,FeCoNiCrNb_(0.5)Mo_(0.25)高熵合金熔覆层具有良好耐磨性与耐蚀性,激光功率为1400 W时层状交替排列的共晶组织和氧化物薄膜使得熔覆层的耐磨性显著增强,磨损率为0.079 mm^(3)·N^(-1)·m^(-1);当激光功率为1300 W时,熔覆层具有最低的自腐蚀电流密度1.716×10^(-6) A·cm^(-2)。FeCoNiCrNb_(0.5)Mo_(0.25)高熵合金激光熔覆层的腐蚀机理为FCC相优先腐蚀,共晶组织的存在在一定程度上降低了熔覆层的耐蚀性;具有良好共晶组织的熔覆层(1400 W)的耐蚀性相对有所降低,自腐蚀电流密度为4.332×10^(-6) A·cm^(-2)。Objective The stern shaft is an important device for the power transmission of ships.However,corrosion is the main failure mode for stern shafts,which are subjected to the attack of Cl-and microorganisms in seawater for a long time in a marine environment with high salt and humidity.The vibration and shock of the ship stern shaft aggravate the wear of the stern shaft.The traditional anticorrosion strengthening of the ship stern shaft surface involves coating its surface with anticorrosion coatings,such as ethylene resin,epoxy resin,and chlorinated rubber.Although these anticorrosion coatings protect ship stern shafts to a certain extent,most are toxic and harm the natural environment,which seriously violates the current trend of green development.Therefore,developing a green,clean,and pollution-free surface modification method for ship stern shafts has not only economic value,but also broad environmental value.An attempt is being made to develop a eutectic high-entropy alloy based on laser cladding technology to provide an effective method for green anticorrosion and wear-resistant modification of ship stern shaft surfaces.Methods The base material was 42CrMo steel.In an argon atmosphere,FeCoNiCrNb_(0.5)Mo_(0.25)high-entropy alloy cladding layers were prepared using a laser with a spot diameter of 4 mm and a scanning speed of 3 mm/s at five different laser powers(1200,1300,1400,1500,and 1600 W).The phase compositions of the cladding layers were analyzed using X-ray diffraction.The microstructures of the cladding layers were observed by scanning electron microscopy.The hardness values of the cladding layers were measured using a Vickers hardness tester.Friction and wear experiments were conducted using a multifunctional friction and wear tester.The corrosion resistances of the cladding layers were tested using an electrochemical workstation.Results and Discussions With the increase in laser power,the molten pool depth of the high-entropy alloy cladding layers increases(Fig.3).FeCoNiCrNb_(0.5)Mo_(0.25)entropy alloy

关 键 词：激光技术 激光熔覆 高熵合金 激光功率 共晶组织 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG113.12[金属学及工艺—金属学]