| Copper alloy which has high strength and high conductivity is a kind of important function material. And it is extensively applied to the down-lead frame of integrate circuit, the head of resistance welding, the trolly wire of electric engine and so on. The situations above are high stress and high electric current when they work, so their materials need have high strength and high conductivity. But it is a conflict between high strength and high conductivity for copper alloy which is made by traditional method. So the research of the high strength and high conductivity copper alloy is an urgent affairs.The hypereutectic Cu-Cr alloy autogenously composite material were made with heated mould continuous casting process, in which Cu phase and Cr phase grow interphasely along the solidification direction. Cr fiber acts as strength and Cu matrix acts as electrical conductivity. In this way, difficulties of soakage dissolve in artificial composite, and chemistry reaction can be avoid. Two phase interphases get along well under low energy state. The specimen have excellent hot stability and high temperature performance.It is very difficult to cast Cu-Cr alloy which contain high Cr content, because Cr has high melting point, Cu-Cr alloy have large range of solidification temperature, the solution distribution coefficient is low and in high temperature, Cr is easy oxidable. In the experiment, the high-frequency inductive heaters are improved and their powers are increased, which increase and stabilize mould temperature gradient, shorten S+L two phase range of Cu-Cr alloy during solidification, lighten Cr constitutional super-cooling, ensure excellent surface quality of Cu-Cr alloy.Casting surface quality which is determined by casting parameters, affects the performance of mechanics and electrical conductivity. Hot tearing, scab, breakdown and leakage can be avoided, when casting velocity, cooling water capacity, cooling distance, casting mould temperature and S+L two phase range are available, consequently, the Cu-Cr alloy which has excellent surface quality can be cast. Experiments shows that when melting temperature is 1450 ℃, casting mouldtemperature is 1250°C, casting velocity is 54mm/min and cooling distance is 10mm , Good 14mm wire of Cu-2.74 wt %Cr can be cast.Cu-Cr alloy wires in which the Cr components are respectively 1.29 wt%, 1.48 wt%, 1.81 wt%, 2.03 wt%, 2.55 wt%, 2.74wt% have been cast successfully. Directional solidification microstructure in as-cast specimen is found. When casting velocity is 54mm/min, the Cr component is 2.74wt%, the result showed a tensile strength of 318.5Mpa, elongation 22.35%, and electrical conductivity 34.6% IACS. And their synthetic property is higher than those made by traditional cast process. When Cr component increases from 2.03 wt% to 2.74wt%, the conductivity of Cu-Cr alloy decreases slowly from 35.2%IACS to 34.6%IACS, its tensile strength increases from 277.7Mpa to 319.5Mpa, its elongation decreases from 19.40% to 16.54%. When casting velocity increases from 35mm/min to 54mm/min, though Cr component increases from 1.29 wt% to 1.48wt%, its conductivity increases slowly from 53.7%IACS to 56.5%IACS all the same. Their conductivity increases obviously and their hardness increases somewhat after the heat treatment. After the heat treatment which temperature is 550°C and time is 80 minutes, the conductivity of Cu-Cr alloy in which the Cr component is 2.74wt% is 81% IACS which is the maximum, and its hardness is 105.0HV. When the Cu-Cr alloy in which the Cr component is 2.03wt% is distorted fromO4 to 02, its tensile strength increases from 277.7Mpa to 543.9Mpa, its conductivity decreases slowly from 34.6%IACS to 33.9%IACS, its hardness increases from 83.1HV to 150.7HV.
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