The Preparation And Property Of Multicomponent High Entrophy Alloy

Multicomponent high entropy alloys FeNiMnCuC_0.2Al_x and AlZnMgCu_xMn_y were designed on the basis of composition design criterions. Alloy ingots were prepared by high-frequency induction furnace and mould cast. The crystalline structure of alloy was characterized using X-ray diffraction (XRD). The microstructure and micro area composition of alloy was studied by SEM equipped with EDS. Compressive property was tested on the universal testing machine. Corrosion resistance was also tested.High entropy alloys of FeNiMnCuC_0.2Al_x were all single phase solid solution, and also were FCC solid-solution structure. This could be attributed to that the effect of high mixing entropy did facilitate the formation of simple solid solutions. High entropy alloys of FeNiMnCuC_0.2 exhibited excellent compressive properties. The compressive strength reached 5218Mpa and compression ratio exceeding 75%. With the increase of Al content, the compressive strength of these alloys decreased. When the content of Al reaches x=0.5, the alloy exhibited as brittle fracture. It showed that adding small amount of Al (x=0.1, 0.2) could make FeNiMnCuC_0.2Al_x grain finer, while x=0.5, Primary dendrite grain got growth. According to the results of EDS, dendritic segregation area was found to be Fe, Ni rich, while interdendritic segregation area was Mn, Cu rich. The distribution of C, Al was almost identical.The precipitation of TiC, NbC were investigated when Ti, Nb were added into high entropy alloy FeNiMnCuC_0.2. The results showed that the precipitation of Mn₃C,Fe₃C could be restrained in the alloys, but TiC, NbC could not. It was attributed to that TiC, NbC posses lower Gibbs free energy than the solid solution. The analysis showed that Gibbs free energies of these alloys were between NbC and Mn3C. For these alloys, Ti addition could refine grain and improve compressive strength and hardness. But the strengthening effect of Ti addition is not evident.In view of multicomponent high entropy alloys had fine corrosion resistance, multicomponent alloy was also designed in the paper which consisting of Zn, Al and Mg component in near equal atomic proportions. had also designed in this paper. It was studied the effect of the alloy addition on electrochemical performance of the multicomponent alloys. For the alloys cosisting Zn, Al and Mg only it indicated that ZnAlMg_0.5 had fine comprehensive properties: Electrode-potential, theoretical generated energy and current efficiency were -1.123V, 1539A·h/kg, and 76.6%, respectively, dissolution of anode surface was also fine. When Cu was added into ZnAlMg_0.5, Cu could increase corrosion resistance and improve anode surface dissolution of these alloys, while electrode-potential and theoretical generated energy would be decreased. Excessive Cu would have a disadvantageous effect on electrochemical performance because of Cu segregation. ZnAlMg_0.5Cu_0.4 and ZnAlMg_0.5Cu_0.6 had fine performances. When Mn was added into ZnAlMg_0.5Cu_0.4 and ZnAlMg_0.5Cu_0.6, Mn could decrease current density and increase corrosion resistance. But meanwhile, this would decrease other performances of these alloys. So Mn was suitable for a small addition.