冷喷涂辅助原位合成FeCo_(x)CrAlCu高熵合金涂层组织性能研究

Microstructure and Performance of Cold Spray-Assisted In-situ Synthesized FeCo_(x)CrAlCu High Entropy Alloy Coating

利用冷喷涂辅助原位合成高熵合金涂层的方法,在45^(#)钢基体表面制备出不同Co含量的FeCo_(x)CrAlCu(x=0,0.5,1,1.5,2)高熵合金涂层。通过XRD、SEM、EDS、TEM、显微硬度计、磨料磨损试验机、电化学工作站等设备,检测分析了Co含量的变化对合金涂层相结构、显微组织、硬度、耐磨性及耐腐蚀性的影响。结果表明:合金涂层是由简单的fcc+bcc双相混合结构组成,Co含量的改变对涂层相结构的影响不大;随着Co含量的增加,合金涂层中的枝晶数目增加,并且得到明显粗化,枝晶内富集Fe、Cr、Co元素,枝晶间富集Cu元素,Al元素均匀分布在整个涂层中;随着Co含量的增加,硬度先增加后减小,在x=1时合金涂层硬度达到最大,其值为5556 MPa;合金涂层中最小的摩擦系数为0.361;在质量分数为3.5%NaCl腐蚀介质中,合金涂层相比与45^(#)钢基体具有较正的自腐蚀电位,说明涂层耐腐蚀性比基体好。

The FeCo_(x)CrAlCu(x=0,0.5,1,1.5,2)high entropy alloy coating was prepared on the surface of 45^(#)steel matrix by cold spray assisted in situ synthesis method.The effects of Co content on phase structure,microstructure,hardness,wear resistance and corrosion resistance of alloy coating were analyzed by XRD,SEM,EDS,TEM,microhardness meter,abrasive wear testing machine,electrochemical workstation and so on.The results show that the alloy coating is composed of simple fcc+bcc two phase mixed structure,and the change of Co content has little influence on the phase structure of the coating.With the increase of Co content,the number of dendrites in the alloy coating increas es and the dendrites get coarsening obviously.The microstructure is enriched with Fe,Cr,Co in the dendrites,and Cu is enriched between the dendrites,and Al is evenly distributed in the entire coating.With the increase of Co content,the hardness first increas es and then decreases.When x=1,the hardness of the alloy coating reaches the maximum value,which is 5556 MPa.The minimum friction coefficient in the alloy coating is 0.361.In 3.5wt%NaCl corrosive medium,the alloy coating ha s a positive self-corrosion potential compared with the 45^(#)steel substrate,indicating that the coating has better corrosion resistance than the substrate.