Preparation Method Of Cu-2.0cr-0.3zr High Concentrations Of Microstructure And Mechanical Properties

High strength high conductivity copper alloys are extensively applied in theelectromechanical, electronic, astronavigation, et al high-tech fileds, it attracts moreand more attention from all the countries in the world. The governments havesupported the material researchers to do research on the preparation technology andbasic theory of them. Especially, as the development of large-scale and superlarge-scale integrated circuit, it requires more for the frame materials of high strengthhigh conductivity copper alloys. The properties of Cu-Fe-P alloys and Cu-Ni-Si alloyscan not meet their needs, So Cu-Cr-Zr alloys have been the thermal topic.Conventional fusion casting, spun-melting rapid-solidification, copperwall-cooling rapid-solidification are conducted to prepare high concentrationCu-2.0Cr-0.3Zr alloy in this article, the effects of different methods of preparation forthe micro-structure and properties are studied, it concludes that:1.The properties of Cu-2.0Cr-0.3Zr ally which is produced by the conventional fusioncasting (technologyl, cold deformation + solution treatment + aging) is littleinfluenced by the magnitude of deformation. After reduction to 50% and 87%, thehardness of the alloys reach the peak value, 128HV and 134HV respectively in 1haging at 450℃. Their relative conductivity is 75%IACS.2. When Cu-2.0Cr-0.3Zr ally is produced by the conventional fusion casting(technology2, solution treatment + cold deformation + aging), the more reduction itis deformed, the sooner it reaches the peak hardness value. When aging at 450℃,the 50%-deformed alloy reaches a peak hardness value of 160HV in half an hour, atthe same time, its relative conductivity is 76%IACS. Comparatively, the80%-deformed alloy reaches its peak hardness value, 164HV, in only 6 min, and itsconductivity is the same as the 50%-deformed alloy. It seems that the technology 2is better than the technology 1.3. Compared with conventional solution treatment, the solid solubility of the rapidsolidified Cu-2.0Cr-0.3Zr was increased greatly, the crystal grain was refinedsharply, the dendritic segregation was decreased and the microscopic structure ofthe alloy was optimized.4. The degree of hardness of Cu-2.0Cr-0.3Zr alloy made by spun-melting is 103HV,and it is increased 61% than conventional solution (64HV). But its conductivitywas decreased rapidly to 22%IACS. After aged at 450℃for 4h, the degree of hardness goes up to 184HV, and the conductivity reaches to 57%IACS.5. The Cu-2.0Cr-0.3Zr block prepared by water-cooled copper die has similarperformance as Cu-2.0Cr-0.3Zr thin strip made by melt-spinning. The hardness ofthe alloy is 108HV at rapid solidified state, and the conductivity is 28%IACS. Afteraged at 450℃for 4h, the hardness is 200HV, and the conductivity is 65%IACS.Aged after 80% cold deformation, the hardness increased further, and it reaches thepeak value when aged at 450℃for 4h, the hardness is 231HV, and the conductivityis 68%IACS.6. The TEM observation shows that the particles in the rapid solidifiedCu-2.0Cr-0.3Zr are body-centered Cr particles, the solute atoms segregation at theprimary stage of aging, the last precipitated phases are Cu₁₀Cr₇ and Cr.7. After annealing 1h at 900℃, the grains of rapid-solidification Cu-2.0Cr-0.3Zr alloygrow a little, it keeps the fine-grained strengthening effect. Its micro-hardnessremains 84HV, it implies that the alloy performs an excellenthigh-temperature-softening resistance.8. The principal strengthening mechanism in Cu-2.0Cr-0.3Zr alloy is cold-deformedstrengthening, fine-grained strengthening, and dispersion strengthening. The maineffect factors for the relative electrical conductivity in Cu-2.0Cr-0.3Zr alloy are thesize and distribution of the solute atoms in the solid solution and precipitation, thevacancy, dislocation, grain boundary, et al play a small role in this condition.