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| Effect of carbon on microstructure and properties of Al2CoCrCuFeNi high
entropy alloy |
| YANG Hengzhe，ZHANG Senming，SUN Fenger，LIU Heping |
| School of Material Science and Engineering，North University of China，Taiyuan 030051，China |
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Abstract High entropy alloy has the lattice distortion effect, sluggish diffusion effect,“cocktail”effect and the
high entropy effect, which makes it easy for high entropy alloy to obtain stable solid solution structure, nanostructure
and even amorphous structure. Therefore, the alloy has many excellent properties, such as high strength, excellent
hardness, outstanding wear resistance, good temperature stability, corrosion resistance, fatigue resistance and
magnetic properties. Powder metallurgy is one of the most common techniques for preparing high entropy alloys,
which can obtain bulk alloys with fine grains and uniform structure. In this paper, Al2CoCrCuFeNi and Al2CoCr-
CuFeNiC0.02 high entropy alloy had been designed. The influence of C on the microstructure and properties of the alloy
was studied. Meanwhile, the strengthening mechanism of the alloy was discussed based on the calculation of
theoretical hardness value. In this paper, mechanical alloying and powder metallurgy were used to obtain the high
entropy alloy, the powdered alloy was synthesized by high-energy ball milling, then the bulk alloy was formed after
sintering. The microstructure and properties of the alloy were characterized by X-ray diffraction, metallographic
microscope and Vickers hardness tester. Through the model, the phase composition and hardness of the alloy were
predicted and verified. At the end of the paper, the strengthening mechanism of the high entropy alloy is given.
The Al2CoCrCuFeNi and Al2CoCrCuFeNiC0.02 high entropy alloys are successfully prepared by powder metallurgy
method. After mechanical alloying, some elements are not completely dissolved into the solid solution to form a
solid solution alloy, but through the subsequent sintering, a solid solution alloy with FCC+BCC or FCC+ ordered BCC(B2) crystal structure is obtained. According to XRD results，BCC and B2 phases are the main phases of
Al2CoCrCuFeNi and Al2CoCrCuFeNiC0.02 high entropy alloys, respectively. This is consistent with the results calculated
by the solid-solution formation rule for high entropy alloy. The hardness of alloys is 208 HV and 328 HV,
respectively, which is very close to the strength calculated by the model then is converted to hardness. The addition
of carbon has a significant contribution to the strength of the high entropy alloy, which makes the hardness increase
about 58% compared with the alloy without carbon. The high entropy alloy prepared in this paper has a
favorable composite strengthening mechanism, and the strengthening derives from the comprehensive contribution
of multiple factors.
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Received: 20 May 2021
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Corresponding Authors:
刘和平（1975—），男，博士，副教授，硕士生导师，主要研究领域固态相变，先进超高强度钢研发，金属材料表面技术，金属基复合材
料，新能源材料增材制造技术及器件。
E-mail: 690894833@qq.com/peace666@126.com
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2022, Vol. 32 
