激光熔覆FeCrNiTax共晶中熵合金涂层组织与性能研究  

Investigation on Microstructure and Properties of Laser-Cladding FeCrNiTax Eutectic Medium-Entropy Alloy Coating

作　　者：叶馥宇 杨键 孙潘杰 王星宇 崔承云[1] Ye Fuyu;Yang Jian;Sun Panjie;Wang Xingyu;Cui Chengyun(School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China)

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《中国激光》2023年第20期104-113,共10页Chinese Journal of Lasers

基　　金：江苏大学工业中心大学生创新实践基金(ZXJG2022038)。

摘　　要：采用激光熔覆技术在304不锈钢表面制备了FeCrNiTax(原子数分数x=0,0.2,0.4,0.6,0.8)共晶中熵合金涂层(EMEACs),探究了Ta元素含量对合金涂层的微观组织、硬度和耐磨性的影响。结果表明:面心立方(FCC)相FeCrNi中熵合金涂层(MEACs)在加入Ta元素后,引入了硬质Laves相,形成了与FCC相交且耦合的原位纳米层状共晶结构。当x<0.4时该中熵合金为亚共晶结构,其微观组织由FCC相和共晶组织组成。当x=0.4时合金达到共晶点,存在完全片层共晶组织。当x>0.4时合金为过共晶结构,组织由共晶组织和Laves相组成。与基体相比,所制备的FeCrNiTax涂层的硬度值有明显提升,其中x=0.8时合金涂层的维氏硬度值最高,高达705.3 HV,约为不锈钢基体的3.7倍。随着维氏硬度的提高,该合金涂层的耐磨性也得到显著改善,FeCrNiTa_(0.8)合金具有最佳的耐磨性,磨损形式以黏着磨损和氧化磨损为主。Objective To improve the relatively low hardness and unsatisfactory wear resistance of 304 stainless steel,corresponding surface coatings with high hardness and wear resistance are prepared in this study using the laser cladding surface modification technology.Accordingly,the service life of 304 stainless steel is extended.Medium-entropy alloys(MEAs)are derived from high-entropy alloys(HEAs)and primarily comprise three to four major elements.Compared with traditional alloys,MEAs have unique phase structures and excellent mechanical properties.Based on the design concept of HEAs with unequal atomic and eutectic structures,Ta is incorporated into FeCrNi MEAs and its content is adjusted to realize FeCrNiTax eutectic medium-entropy alloy coatings(EMEACs).Using this in-situ nanoscale laminate structure which combines both soft and hard phases,the overall strength and wear resistance of the alloy are greatly improved,while considerable plasticity is maintained,achieving a balance between strength and plasticity.In addition,the rapid laser cladding solidification technology is beneficial for refining the characteristic structure and improving the mechanical properties of the coating.Methods In this study,five FeCrNiTax(atomic fraction x=0,0.2,0.4,0.6,and 0.8)alloy coatings with varying Ta contents are designed as research samples.The 304 stainless steel is chosen as the substrate for laser cladding.Elemental powders with different components are uniformly mixed and preplaced on a polished substrate using a planetary ball mill.The coatings are prepared using a laser cladding device with the laser power of 1400 W,scanning speed of 8 mm/s,spot diameter of 3.6 mm,and overlap rate of 35%.The crystal structures of the coatings with different Ta contents are analyzed using X-ray diffractometer(XRD),and their microstructures and chemical compositions are characterized via scanning electron microscope(SEM).Subsequently,the Vickers hardness values of the coatings from the cladding layer to the substrate are measured using a Vicke

关 键 词：激光技术 激光熔覆 中熵合金涂层 共晶结构 硬度 耐磨材料 

分 类 号：TN249[电子电信—物理电子学]