| The present study aims to refine the grain size of Cu-Ni alloy by adding metal element Ti into Cu-Ni alloy to make compounds generate Cu4 Ti phase,Ni2 Ti phase and a small amount of NiTi phase. Meanwhile, adding Ti into Cu-Ni alloy can produce dispersion strengthening and increase hardness of Cu-Ni alloy.After aging treatment of Cu-Ni-Ti alloy, the precipitated phase will be gradually increased, solid solution of alloy elements in the copper will be reduced, ability of the electron scattering power will be decreased, therefore, electrical conductivity of Cu-Ni-Ti alloy will be increased.In this research, Cu-Ni-Ti alloy components are designed, forged, rolled and aging treated. The Cu-Ni-Ti alloy will be analyzed by metallographic microstructure analysis, X-ray diffraction analysis, scanning electron microscopy(SEM) analysis, energy spectrum analysis and differential thermal analysis. The comparison between Cu-Ni-Ti alloy and C7025 alloy( Cu-3.0Ni-0.65Si-0.15 Mg is a commonly used lead frame materials with electrical conductivity being 50%IACS and Vickers hardness being 200Hv),with of the reasonable component design of Cu-Ni-Ti alloy, effectively avoided Ti alloy’s influence on the electrical conductivity of Cu-Ni alloy. The electricalconductivity of Cu-Ni-Ti alloy is 54.17% IACS and its Vickers hardness is201 Hv. Electrical conductivity and hardness of Cu-Ni-Ti alloy will be increased by adding alloy elements Zinc and Stannum on the basis of Cu-Ni-Ti alloy. As a result, Cu-Ni-Ti alloy comprehensive property will be further improved.Research is carried out by the following analytical means: optical microscope(OM), differential thermal analyzer(DTA), X-ray diffraction(XRD) and scanning electron microscope(SEM), EDS energy spectrum analyzer and so on.And the microstructure, second phase and component of Cu-Ni-Ti-Zn alloy and Cu-Ni-Ti-Sn alloy are analyzed. Combined with differential thermal analysis after aging phase was studied. At the same time, the Miedema model is adopted to the thermodynamic calculation to producing phase sequence of Cu-Ni-Ti- Zn alloy.The experiment result shows:the combination property of Cu-Ni-Ti alloy is superior to C7025 alloy. Therefore, as a new type of lead frame of copper alloy material, Cu-Ni-Ti alloy have a good electrical conductivity and hardness.When metal element Sn was added into Cu-Ni-Ti alloy, a new compound phase Sn3Ti5 came out. It had a significant effect on grain refinement of Cu-Ni-Ti alloy and improved the strength of the Cu-Ni-Ti alloy. Meanwhile, the addition of metal element Sn could enhance the toughness and rolling processing performance of Cu-Ni-Ti alloy. The conductivity and hardness of copper alloy were also improved to some extent. The addition of metal element Zn content in the alloy, the grain size of the alloy sample decreased. When the Zn content inCu-Ni-Ti alloy was up to a certain extent, the grain size did not continue to decrease and the hardness value dropped. Therefore, when the Zn content in the Cu-Ni-Ti alloy was 0.05wt%, Cu-Ni-Ti-Zn alloy had optimal mechanical properties. The addition of metal element Zn could cause the decreasing conductivity of Cu-Ni-Ti alloy, but when a small amount of Zn was added, the conductivity of Cu-Ni-Ti alloy did not change significantly. |
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