Research On Interface Microstructure And Properties Of Cu(Al)/EHEA Cladding Ingots

Metal cladding material is a new type of composite material that combines two or more kinds of metal materials through certain processing technology.This kind of material can combine the advantages of its constituent materials and meet the performance requirements of the material under special circumstances by improving the advantages and making up the disadvantages.Eutectic high entropy alloy AlCoCrFeNi_2.1?hereinafter referred to as EHEA?has the high strength,high hardness,high temperature creep resistance,high temperature oxidation resistance,corrosion resistance,good casting fluidity,plasticity and processing properties.No EHEA cladding material have been reported so far.In this paper,Cu/EHEA clad ingots with weak interfacial reaction and Al/EHEA clad ingots with strong interfacial reaction were prepared by solid-liquid bonding method,and the composite ingots were hot-rolled.The interfacial structure,composition,phase,mechanical properties of the two composite ingots and the effect of pouring technology and rolling on the interfacial interface were systematically analyzed.The preparation of Cu/EHEA stratified ingots casting and hot rolling experiment results show that:Cu/EHEA composite ingots can be prepared by solid-liquid method,combining way as the melting and diffusion.The interfacial structure is a zipper type,and the interfacial bonding strength is higher than that of pure copper.Preheating EHEA and increasing the pouring temperature of copper solution are beneficial to increase the thickness of diffusion layer and the melting depth of B2 phase.After hot rolling,The FCC phase in EHEA at the interface enters the Cu side.With the increase of the reduction rate,the size of FCC phase entering the Cu side decreases,its number increases and its distribution is uniform.After hot rolling,the casting shear strength gradually increases to 75MPa,80MPa and 90MPa when the reduction rate is 20%,30%and 40%.Hot rolling can improve its corrosion resistance.The preparation of Al/EHEA composite ingots and the hot rolling test results show that:a violent interfacial reaction occurrs between EHEA and Al,and brittle intermetallic compounds such as Al₂Fe,AlCr₂,Al₃Ni,AlNi,AlNi₃ and AlCo are generated in the interfacial layer,which lead to a decrease in the bonding strength of Al/EHEA composite ingots.The higher the casting temperature,the easier the formation of intermetallic compounds.The intermetallic compounds in the reaction layer are broken and distributed at the interface after hot rolling,which improves the interfacial bonding strength of Al/EHEA composite ingots.There is still a gap between Al and EHEA when the reduction rates of hot rolling are 15%and 24%.The gap at the bonding interface disappears when the reduction rate is 30%.Al and EHEA achieve a good combination,and the maximum shear stress at the interface is 43 MPa.