Study Of Design,Manufacture,Microstructure And Properties Of ZrFeCrTiCu/Nb High Entropy Alloy

Zr alloy is mainly used in the nuclear power field.Introducing the concept of high-entropy alloys into the design of traditional zirconium alloy materials is expected to obtain high-strength structural materials.Therefore,in this paper,the Zr_33.2Fe_36.2Cr₁₃Ti₇Cu_10.6 high-entropy alloy powders were prepared by mechanical alloying using Zr,Fe,Cr,Ti,and Cu powders as raw materials.And the effects of different mechanical alloying parameters on the mechanical alloying process were studied.The Zr Fe Cr Ti Cu and Zr Fe Cr Ti Nb high-entropy alloys were also prepared by the vacuum melting.Based on the analysis of phase,microstructure and mechanical property,the influence of alloy composition on microstructure and properties was explored.The heat treatment process is used to reveal the influence of solution treatment temperature on the structure and properties of the alloy.The main content and conclusions of the paper are as follows:（1）By changing the milling time,the type and mass fraction of the process control agent in the mechanical alloying process,it is found that with the increase of ball milling time,the Zr_33.2Fe_36.2Cr₁₃Ti₇Cu_10.6 high-entropy alloy powder has refined grain size and increased lattice strain,however the alloying effect is not good.There is the less the mass fraction of process control agent,the more advanced and more serious the cold welding phenomenon will appear.Stearic acid has a good effect of inhibiting cold welding.（2）Due to the poor mechanical alloying effect,this paper smelted the Zr Fe Cr Ti Cu high-entropy alloys with different compositions,and the structure and properties were explored.It is found that the Zr Fe Cr Ti Cu high-entropy alloys has a HCP+BCC two-phase structure,and there is a certain degree of Cu segregation.With the increase of Cu content,the number of Zr₂Cu phases increases,and the material density and hardness increase at the same time,the hardness is up to 970.3 HV.The compressive strength increases monotonously,and the compressive strain increases first and then decreases.The Zr_33.2Fe_36.2Cr₁₃Ti₇Cu_10.6 high-entropy alloy showed the best comprehensive mechanical properties.（3）The Zr Fe Cr Ti Nb high-entropy alloys were prepared by smelting.The structure and properties of the Zr Fe Cr Ti Nb high-entropy alloys with different compositions were explored.It was found that the Zr Fe Cr Ti Nb high-entropy alloys showed a multi-phase structure.With the increase of Nb content,the band-like second phase increased,resulting in refinement the structure.At the same time,the density and hardness increase,the highest hardness is 1068.7HV.The compressive strength and compressive strain both increase first and then decrease,the Zr_38.1Fe_37.4Cr_13.4Ti_7.3Nb_3.8 has the best comprehensive mechanical properties.（4）The heat treatment with different solution treatment temperatures was conducted on the Zr35.3Fe36.5Cr13.1Ti7.1Cu8 and Zr38.1Fe37.4Cr13.4Ti7.3Nb3.8 high-entropy alloy.The results show that with the increase of solution treatment temperature,the content of the second phase gradually decreased.When the solution treatment condition is 1050℃,the densely precipitated second phase greatly of the Zr_35.3Fe_36.5Cr_13.1Ti_7.1Cu₈and Zr_38.1Fe_37.4Cr_13.4Ti_7.3Nb_3.8 high-entropy alloy refined the grain,thus this sample has the best compressive properties.The compressive strength,yield strength,and plastic strain of the the Zr_35.3Fe_36.5Cr_13.1Ti_7.1Cu₈ high-entropy alloy are 1293 MPa,259 MPa,and 5.7%,respectively.The compressive strength,yield strength,and plastic strain of the Zr_38.1Fe_37.4Cr_13.4Ti_7.3Nb_3.8high-entropy alloy are 1583 MPa,317 MPa,and 5%,respectively.