表面技术2025，Vol.54Issue(9)：189-203,15.DOI:10.16490/j.cnki.issn.1001-3660.2025.09.016
TC4 钛合金表面激光熔覆AlCoCrFeNi高熵合金的组织与性能
Microstructure and Properties of AlCoCrFeNi High-entropy Alloy Laser Cladding on TC4 Titanium Alloy Surface
摘要
Abstract
The disadvantages of titanium alloys such as poor resistance to high temperature oxidation,low hardness and poor wear resistance limit the use of titanium alloys in practical applications,and surface modification techniques can be considered to improve the surface properties of titanium alloys.In this paper,the microstructure and properties of AlCoCrFeNi high-entropy alloy cladding layer laser melted on TC4 titanium alloy surface are investigated,and high-temperature oxidation resistance test,hardness test and abrasion resistance test are carried out on the cladding layer and the substrate,and the specimens are observed by test methods such as OM,SEM,EDS and XRD,to analyze the microstructure evolution law of the high-entropy alloy cladding layer in the process of laser cladding and the improvement of the properties of the cladding layer on the TC4 substrate.The experimental results show that the best cladding effect is achieved when the laser process parameters are 1 400 W and 12 mm/s,and the AlCoCrFeNi high-entropy alloy cladding layer forms a good metallurgical bond with the TC4 substrate.The cladding layer is mainly composed of FCC and BCC phases,in which the BCC phase 1 is an AlNi2Ti phase and the BCC phase 2 is a CrFe phase,and the phase composition of the TC4 substrate is α-Ti and β-Ti.The SEM and EDS results can clearly show the microstructure transformation law in the process of fusion cladding,and from the combination of the cladding layer and the substrate upward.There is a heat-affected zone,a planar crystal zone,a columnar crystal zone,and an equiaxial crystal zone.The formation of microstructures in each region is controlled by the temperature gradient(G)and the crystal growth rate(R),and the G/R value is an important criterion for controlling the growth pattern of crystals.The magnitude of heat input also affects the growth of equiaxial crystals and columnar crystals.Under the condition of 800℃,the oxidized surface morphology of AlCoCrFeNi cladding layer is good,and no obvious oxide skin is formed,while the surface of the TC4 substrate has already appeared a thicker oxide film and some of them have been cracked off;The oxidized weight gain rate of the TC4 substrate and the AlCoCrFeNi cladding layer is 28.546 mg/cm2 and 1.318 mg/cm2,respectively.And the oxides on the surface of high-entropy alloy are mainly Al2O3,TiO2 and(Cr,Fe)2O3,and the oxides on the surface of the TC4 substrate are mainly TiO2 and Al2O3.The oxide film of the AlCoCrFeNi alloy cladding layer is very thin,with a thickness of less than 1 μm,but the TC4 surface forms an oxide film of more than 100 μm.The average hardness of the cladding layer is 1.95 times of the average hardness of the substrate,which reaches 677.0HV.At room temperature,the coefficients of friction of the TC4 substrate and AlCoCrFeNi cladding layer are 0.398 and 0.473,respectively,but TC4 has more relative wear.The laser cladding of AlCoCrFeNi high-entropy alloy on the surface of TC4 titanium alloy significantly enhances the high-temperature oxidation resistance,hardness and wear resistance of the TC4 titanium alloy substrate.关键词
TC4 钛合金/激光熔覆/高熵合金/组织转变/抗高温氧化性/耐磨性Key words
TC4 titanium alloy/laser cladding/high-entropy alloy/microstructure transformation/high temperature oxidation resistance/wear resistance分类
金属材料引用本文复制引用
程一凡,李峰光,廖露海,刘建永,杨伟,顿亚鹏..TC4 钛合金表面激光熔覆AlCoCrFeNi高熵合金的组织与性能[J].表面技术,2025,54(9):189-203,15.基金项目
湖北省教育厅科学技术研究计划重点项目(D20221801) （D20221801）
汽车动力传动与电子控制湖北省重点实验室(湖北汽车工业学院)项目(ZDK12023B06) Hubei Provincial Department of Education Science and Technology Research Key Project(D20221801) （湖北汽车工业学院）
Hubei Key Laboratory Automotive Power Transmission and Electronic Control(Hubei Automotive Industry Institute)Project(ZDK12023B06) （Hubei Automotive Industry Institute）
