金刚石与磨料磨具工程2026，Vol.46Issue(1)：25-33,9.DOI:10.13394/j.cnki.jgszz.2025.0037
水冷时间对CoCrNiCuFe高熵合金组织与性能的影响
Effect of water cooling time on microstructure and properties of CoCrNiCuFe high entropy alloy
摘要
Abstract
Objectives:The preparation of precursor powders for high-entropy alloys(HEA)typically employs the mechanical alloying(MA)method.The composite powder obtained after MA possesses high energy and is prone to spontaneous combustion.To facilitate handling in air,the powder is water-cooled,followed by sintering into blocks via spark plasma sintering(SPS).This study investigates the effects of water-cooling time on the microstructure and properties of the CoCrNiCuFe high-entropy alloy.Methods:Water-cooled MA is used to prepare HEA composite powder,and SPS technology is used to sinter the composite powder.The sintered body is subjected to rough grinding,fine grinding,and polishing to prepare a bright and scratch-free sample.X-ray diffraction(XRD)is used to detect the phases of the powder and sintered body;scanning electron microscope(SEM)is used to detect the element distribution and morphology of the powder and sintered body;a visible porosity and bulk density tester is used to test the apparent porosity of the sintered body;a Vickers hardness tester is used to measure the microhardness of the sintered body;a universal testing machine is used to test the compressive performance of the sintered body;and a synchronous thermal analyzer is used to test the thermal stability of the sintered body.The composition,morphology,and properties of the water-cooled sample are systematically analyzed.Results:The powders cooled for 2,4,and 6 h all have a Ni rich FCC structure phase and a Cr-rich BCC structure phase,and the sintered body contains FCC1 phase,FCC2 phase,and Cr2O3 phase.The average grain sizes of the FCC1 phase in the sintered bodies after 2,4,and 6 h of water-cooling are 69.1,58.7,and 59.8 nm,respectively.The average grain sizes of the FCC2 phase are 62.7,56.9,and 57.8 nm,respectively.The average grain sizes of the Cr2O3 phase were 50.3,42.7,and 44.2 nm,respectively.Water-cooling reduces the agglomeration of CoCrNiCuFe powder and refines the microstructure and grain size.After 4 h of water-cooling,the scanning morphology of the powder shows slight clumping,with a large amount of powder in the form of thin flakes and a small amount in the form of fragments.However,the distribution of the 5 types of powder is uniform,indicating that CoCrNiCuFe powder is MA in air and has a low degree of oxidation.After water-cooling,a thin oxide film adheres to the surface of the powder,which prevents spontaneous combustion of the material during air exposure and achieves a passivation effect.In addition,the surface structure of the sintered body after 4 h of water-cooling is uniform,without obvious pores,and the high-entropy alloy phase is circular in shape,while the Cu-rich phase is irregular in shape.Through analysis of the point scan results at point 1,the five elements Co,Cr,Ni,Cu,and Fe are evenly distributed without precipitation or enrichment,indicating that these five metal elements are well dissolved together to form a high-entropy alloy phase.A high content of Cu element appears at point 2,indicating segregation of Cu(bright green area),and the enrichment of Cu element surrounds the HEA phase.The black spot at point 3 corresponds to a localized enrichment zone of Cr element,indicating that Cr is not fully dissolved in the matrix and forms an enrichment zone at the grain boundary during the sintering process.The grain structure between CoCrNiCuFe high-entropy alloy phases is an equiaxed dendritic structure,while the grain structure between Cu-rich phases is an irregular dendritic structure.The eutectic structure of FCC1 phase,FCC2 phase,and oxide phase can be attributed to the hysteresis diffusion effect of HEA.Meanwhile,the sintered body after 4 h of water-cooling has a density of 94.6%,a hardness of 460 HV0.5,and a compressive strength of 1 388 MPa.Thermal analysis tests show that the initial oxidation temperature of the sintered body is 1 082.9℃,and the final oxidation temperature is 1 152.3℃,resulting in a 28.4%increase in oxidation mass.Conclusions:(1)Water-cooling refines the grain size of CoCrNiCuFe HEA,inhibits secondary dendrite growth,and reduces powder agglomeration of HEA.(2)The physical properties of CoCrNiCuFe HEA after 4 h of cooling are excellent,with density,hardness,and compressive strength reaching 94.6%,460 HV0.5,and 1 388 MPa,respectively.(3)CoCrNiCuFe HEA has excellent oxidation resistance after 4 h of cooling,with an initial oxidation temperature of 1 082.9℃and a final oxidation temperature of 1 152.3℃.The oxidation mass increases by 28.4%,which is due to the selective oxidation behavior of the HEA and the dense oxide film protection formed by Cr element oxidation.关键词
高熵合金/机械合金化/水冷/放电等离子烧结Key words
high-entropy alloy/mechanical alloying/water cooling/spark plasma sintering分类
矿业与冶金引用本文复制引用
刘杰,任海波,张逸忠,刘光辉,李艳国,邹芹..水冷时间对CoCrNiCuFe高熵合金组织与性能的影响[J].金刚石与磨料磨具工程,2026,46(1):25-33,9.基金项目
河北省自然科学基金资助项目(E2024203136) （E2024203136）
秦皇岛市科学技术研究与发展计划项目(202302B005) （202302B005）
镇江市"金山英才"产业强市领军人才引进计划(丹财[2023]183号) （丹财[2023]183号）
丹阳市"丹凤朝阳"产业强市领军人才引进计划(丹阳人才办[2023]24号). （丹阳人才办[2023]24号）
