| Copper alloy/austenitic stainless steel bimetallic composite can give full play to the heat and conductivity of copper and the high strength and corrosion resistance of stainless steel,and it is widely used in shipbuilding,chemical industry,electric power,military industry and other fields.However,the defects that cracks and holes are easy to form at the interface of copper alloy/austenitic stainless steel limit the application range of copper alloy/austenitic stainless steel bimetallic composites.In order to improve the properties of copper alloy/austenitic stainless steel bimetallic composites,it is necessary to understand the factors that affect the interfacial bonding of copper alloy/austenitic stainless steel from the microscopic point of view.In this paper,the interface structure of Cu/γ-Fe and the influence of common alloying elements in copper(Co,Cr,Ni,Si,Ti,Zn,Al,Fe,Pb,Sn)on the interface bonding of Cu/γ-Fe are calculated and studied by first principles.The main research contents and conclusions are as follows:(1)The exchange correlation functional and calculation parameters are selected,and the electrical properties,mechanical properties and thermodynamic properties of Cu and γ-Fe are calculated by first principles.The results show that both Cu and γ-Fe have good electrical conductivity and metallic properties.γ-Fe has stronger deformation resistance than Cu,and its elastic anisotropy is higher than that of γ-Fe.Both Cu and γ-Fe have intrinsic stability.(2)Three kinds of Cu(100)/γ-Fe(100)interfaces,four kinds of Cu(110)/γ-Fe(110)interfaces and two kinds of Cu(111)/γ-Fe(111)interfaces were constructed.Stable interface configurations are obtained,and different interface configurations are analyzed in combination with the density of states.The results show that the most stable interface configuration among the three Cu(100)/γ-Fe(100)interface models is Cu(100)/γ-Fe(100)-down,and the most stable interface configuration among the four Cu(110)/γ-Fe(110)interface models is Cu(110)/γ-Fe.In the interface model,the most stable interface configuration is Cu(111)/γ-Fe(111)-down,and the interface with the largest interface bonding work is Cu(100)/γ-Fe(100)-down,and a Cu-Fe metal bond is formed at the interface.(3)The segregation of alloying elements on the Cu side of Cu/γ-Fe interface and the effect of alloying elements on the wettability of Cu/γ-Fe interface were studied,and the influence of segregation of alloying elements on the properties of Cu/γ-Fe interface was studied by Interface distortion,combining differential charge density and density of states.The results show that,for Cu(100)/γ-Fe(100)interface,Cr,Pb and Sn can’t segregate at the interface,but Co,Cr,Si,Ti,Al and Fe can segregate at the interface and increase the wettability of the interface,while Zn can segregate at the interface but decrease the wettability of the interface.For Cu(110)/γ-Fe(110)interface,Co,Cr,Pb and Sn can’t segregate at the interface,while Ti,Ni,Si,Al and Fe can segregate at the interface and increase its wettability,while Zn can segregate at the interface but reduce its wettability.For Cu(111)/γ-Fe(111)interface,Cr,Ti,Zn,Al,Pb and Sn can’t segregate at the interface,but Co,Ni,Si and Fe can segregate at the interface and increase the wettability of the interface.The analysis of the electronic structure shows that the alloy atoms that the alloy atoms that can segregate at the Cu/γ-Fe interface form chemical bonds with γ-Fe.(4)The tensile mechanical curves of Cu/γ-Fe interface before and after segregation of alloying elements are calculated,and the influence of segregation of alloying elements on the mechanical properties of Cu/γ-Fe interface is studied by combining fracture position,tensile strength,theoretical toughness,Griffith fracture energy,critical strain and charge density.The results show that the Cu/γ-Fe interface fractured along the Cu side under the action of tensile stress;Ti segregation at the interface of γ-Fe(100)/Cu(100)will increase the mechanical properties of the interface,while Zn segregation at the interface of γ-Fe(100)/Cu(100)will extremely deteriorate the mechanical properties of the interface;Ni segregation at the interface of γ-Fe(110)/Cu(110)will reduce the mechanical properties of the interface,while Ti segregation at the interface of γ-Fe(110)/Cu(110)will greatly deteriorate the mechanical properties of the interface.The segregation of Co and Ni at the interface of γ-Fe(111)/Cu(111)will reduce the mechanical properties of the interface,and the segregation of Si at the interface of γ-Fe(111)/Cu(111)will greatly deteriorate the mechanical properties of the interface. |
PDF Full Text Request