Composite Technology Of Liquid Copper And Solid High Entropy Alloy Under Pulsed Magnetic Field

In order to solve the problem of excessive thickness of Cu/AlCoCrFeNi_2.1 composite layer,the method of compacting liquid copper with solid AlCoCrFeNi_2.1 alloy under pulsed magnetic field was adopted.The effects of molten copper pouring,preheating temperature of mold,pulse voltage and frequency on element distribution,microstructure,thickness of the composite layer and mechanical properties of the composite layer were studied.The optimum composite technology of copper liquid and solid high entropy alloy under pulsed magnetic field was determined.It is found that with the increase of the pulse voltage,the content of various elements in the Cu side of AlCoCrFeNi_2.1 increases and the solidification structure becomes more disorderly.The amount of B2 melted by copper becomes less,the diffusion distance of copper into AlCoCrFeNi_2.1 becomes shorter,and the thickness of the composite layer becomes thinner.The tensile strength of the composite layer decreases and the maximum strain increases.The influence of pulse frequency on the content and thickness of elements in the composite layer is completely opposite to that of pulse voltage.However,with the increase of pulse frequency,the tensile strength of the composite layer increases first and then decreases,and the maximum strain decreases first and then increases.The effect of applied pulse voltage is more obvious than that of pulse frequency.Under the condition that the size of the high entropy alloy isΦ30mm×5mm and the liquid copper is 500g,the best process of preparing Cu/AlCoCrFeNi_2.1 composite by liquid/solid composite method is as follows:casting and preheating temperatures are 1400°C and 400°C,pulse frequency and voltage are 2Hz and 600V,respectively.The total thickness of Cu/AlCoCrFeNi_2.1 composite layer prepared by the best technology can be reduced to 6.20μm,the tensile strength is higher than 192.6MPa,and the maximum strain is greater than 43.8%.