摘要
利用激光熔覆技术在AISI 304不锈钢表面制备了AlCoCrFeNiSi_(x)(x=0.1,0.2,0.3,0.4,0.5)高熵合金涂层。采用XRD、SEM、EDS、TEM、维氏硬度计和电化学工作站等,分析了Si元素对AlCoCrFeNiSi_(x)高熵合金涂层微观组织和性能的影响。结果表明:AlCoCrFeNiSi_(x)高熵合金涂层由体心立方(bcc)固溶体晶粒构成。随着Si含量的增加,Si元素置换固溶使晶格收缩,晶粒逐步细化,纳米尺度球状AlNi相在晶粒内脱溶,少量的Cr_(23)C_(6)碳化物沿晶界析出。微观组织的演化导致涂层的显微硬度升高,最大硬度(HV_(0.3))达到8481 MPa。AlCoCrFeNiSi_(x)高熵合金涂层的热力学腐蚀倾向和均匀腐蚀速率均低于基材AISI 304不锈钢。Si元素的掺杂提高了钝化膜的修复能力和稳定性,使腐蚀机制从自催化发展的点蚀转变为晶间腐蚀。
AlCoCrFeNiSi_(x)(x=0.1,0.2,0.3,0.4,0.5)high-entropy alloy coatings were prepared on the surface of AISI 304 stainless steel by laser cladding.The effects of Si element on the microstructure and properties of the high-entropy alloy were investigated by XRD,SEM equipped with EDS,TEM,Vickers hardness tester,and electrochemical workstation.The results show that the high-entropy alloy coatings consist of solid-solution grains with body-centered cubic(bcc)lattice.With the increase of the Si content,the substitutional solid solution of Si element causes the crystal lattice to shrink,and the crystal grains are gradually refined.Besides,the AlNi phase wit h nano-scale spherical shape is dissolved in the crystal grains,and a small amount of Cr_(23)C_(6) carbides are precipitated along the grain boundaries.The evolution of the microstructure leads to an increase in the microhardness of the coating,and the maximum hardness(HV_(0.3))reaches 8481 MPa.The thermodynamic corrosion tendency and uniform corrosion rate of AlCoCrFeNiSi_(x) high-entropy alloy coating are lower than those of the AISI 304 stainless steel.The doping of Si element improves the repair ability and stability of the passivation film,and promotes the corrosion mechanism to transform from pitting corrosion developed by autocatalysis to intergranular corrosion.
作者
刘昊
高强
郝敬宾
张国忠
胡元
杨海峰
Liu Hao;Gao Qiang;Hao Jingbin;Zhang Guozhong;Hu Yuan;Yang Haifeng(School of Mechanical and Electrical Engineering,China University of Mining and Technology,Xuzhou 221116,China;Jiangsu Collaborative Innovation Center of Intelligent Mining Equipment,China University of Mining and Technology,Xuzhou 221008,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2022年第6期2199-2208,共10页
Rare Metal Materials and Engineering
基金
国家自然科学基金青年基金(51905534)
江苏高校优势学科建设工程资助项目(PAPD)。
关键词
激光技术
激光熔覆
高熵合金
微观组织
显微硬度
腐蚀机制
laser technique
laser cladding
high-entropy alloy
microstructure
microhardness
corrosion mechanism
