Research On Key Technologies And Microstructure And Properties Of Copper/Aluminum Bimetallic Components Prepared By Squeeze Casting

Aluminum alloy and copper alloy are very important non-ferrous metal materials,which are widely used in aerospace,automobile,communication,electric power,semiconductor and daily necessities.With the rapid development of modern science and technology,However,higher requirements are placed on the performance of materials.A single metal material can no longer fully meet the requirements of material service performance,while Cu/Al double alloy components can effectively combine two dissimilar species.The advantages of materials,such as copper’s high electrical and thermal conductivity,wear resistance and aluminum’s light weight,easy welding and low cost etc.At the same time,the irreversibility of resources is also restricting the application of materials.The study of Cu/Al dual alloy components to replace the original copper alloy components can not only achieve the purpose of lightweight materials under the premise of ensuring performance,but also save resources.Therefore,the study of Cu/Al dual alloy components has become an important research direction in the field of materials science and engineering.As an advanced process,squeeze casting is an effective method for preparing Cu/Al double alloy components.Therefore,this paper adopts the squeeze casting solid-liquid composite process to prepare Cu/Al double alloy components,and studies the effect of squeeze casting and gravity casting on Cu/Al double alloy components.The influence of the microstructure and mechanical properties of the Cu/Al dual alloy components,the microstructure,phase composition,distribution and morphology of the Cu/Al dual alloy interface were analyzed,the distribution and mechanical properties of the interface elements were explored,and the properties were obtained by controlling the process parameters.The optimal double alloy component provides an effective method and theoretical basis for the preparation of solid-liquid composite Cu/Al double alloy.In this project,ZL101 aluminum liquid is selected as molten casting liquid,and ZCu Sn10P1 tin bronze is used as preset inlay to prepare Cu/Al double alloy components.Because there is an oxide layer on the surface of ZCu Sn10P1 tin bronze,and it is easy to be oxidized at high temperature,the existence of the oxide film is not conducive to the formation of metallurgical bonding at the double alloy interface.Therefore,the method of electroless nickel plating（Ni-P layer）is used to protect the ZCu Sn10P1 tin bronze from oxidation.The Ni-P layer on the surface can effectively improve the wettability of the surface of the tin bronze and facilitate the expansion of the aluminum alloy melt along its solid alloy surface,forming a good metallurgical bonding interface.Compared with the non-electroless plating,the squeeze-casting Cu/Al double alloy components prepared by electroless Ni-P layer have cracks running through the entire interface in the Cu/Al double alloy interface without electroless plating.The shear strength is 3.87MPa;the Cu/Al double alloy interface prepared by electroless Ni-P layer has a uniform and continuous transition layer,and a good metallurgical bonding interface is formed.The shear strength can reach 28.26MPa,and the interface is composed of It consists of three regions,starting from the copper matrix side:the I region is mainly Ni（Cu）solid solution,the II region is the Ni₃P phase,and the III region is the Al₃Ni phase.The average thicknesses of I,II,and III regions were measured by measuring software to be 10.5μm,0.9μm,and 3.6μm,respectively.On the basis of electroless Ni-P coating,the effects of casting temperature and process parameters（680℃,700℃,720℃）on the microstructure and mechanical properties of gravity-cast Cu/Al double alloy components were studied.The research shows that the casting temperature has a great influence on the average thickness of the intermetallic compound IMCs layer.Compared with 680℃and 720℃,the Cu/Al double alloy components prepared at the casting temperature of 700℃have no cracks,pores,etc.A good metallurgical bonding interface is formed,and the average thickness of the intermetallic compound IMCs layer is the smallest,which is 42.97μm;the interface is composed of solid solutionα（Al）,free fast Al₂Cu,and intermetallic compound IMCs layer.The IMCs layer is composed of Cu_5.6Sn phase,Cu₆Sn₅ phase,Al₄Cu₉ phase,Al Cu phase and Al₂Cu phase with irregular lamellae in order from the copper matrix side.Compared with 680°C,the type、morphology and thickness of the IMCs layer phase changed.When the casting temperature was 700°C,the Al₂Cu₃ phase of the IMCs layer disappeared,and the uneven distribution of Cu₆Sn₅ phase was formed;when the casting temperature was increased to 720°C,the type of the IMCs layer did not change,but the morphology and thickness changed.The effect of casting temperature on the shear performance of Cu/Al double alloy interface is significant.With the increase of casting temperature,the variation law of shear strength is first increased and then decreased.19.83MPa,contrary to the change law of the intermetallic compound IMCs layer with the change of casting temperature,the fracture mode is typical brittle fracture.On the basis of electroless Ni-P plating,orthogonal design experiments were used to study the effect of extrusion casting process parameters（casting temperature,extrusion force,copper rod preheating temperature and die preheating temperature）on the interfacial shear of Cu/Al double alloy components The effect of the process parameters on the shear performance of the Cu/Al double alloy interface was obtained.The primary and secondary order are:casting temperature,extrusion force,copper rod preheating temperature and mold preheating temperature.The influence of the interfacial shear performance of the dual alloy is the most significant,followed by the extrusion force and the preheating temperature of the copper rod;the influence of the preheating temperature of the die on the shear performance of the Cu/Al dual alloy interface is not significant;The orthogonal test is very differential analysis and variance showed that the optimal extrusion casting process parameters were:the casting temperature was 700°C,the extrusion pressure was 90MPa,the copper rod preheating temperature was 300°C and the mold preheating temperature was 300°C,Its shear intensity can reach 28.23MPa.