| With the rapid development of modern industries, the demand for copper alloys with high strength, high hardness, heat resistance, wear resistance and thermal conductivity is increasingly urgent. These copper alloys were widely used in the fields such as Lead Frame materials, high-speed electric locomotives overhead wires, electrical contacts and welding materials, generators, Boiler liners, etc. These alloys were meet intensity requirement, at the same time the conductivity of materials were enhanced as high as possible (above 80%IACS).The copper alloys with high strength and high conductivity was melted by a coreless frequency induction furnace and alloying elements were directly added into alloy liquid. It not only reduced the cost, but also improved the production efficiency. So the method was suitable for an industry production. The continuous casting Cu alloys rod withΦ150mm×5000mrn was produced by the method of vertical semi-continuous casting and water cooling. The hot extrusion alloys bar was produced by Water Seal extrusion process; the finished alloys product was produced by cold drawing.The alloys have been solution treated, ageing and cold drawing. And the effect of aging temperature and the holding time on the hardness and conductivity of the Cu-Zr-Te and the Cu-Zr-Cr alloys with high strength and high conductivity was investigated. The results showed that the hardness of high-strength and high-conductivity copper alloys by solution pretreatment solution plus drawing pretreatment were both gradually increased with ageing temperature and holding time, after reached peak, the hardness decreased slowlyUnder the same temperature and the holding time, the hardness of alloys by solution pretreatment was less than the hardness of pretreatment solution plus drawing, and the hardness of the Cu-Zr-Cr alloy was higher than that of Cu-Zr-Te alloy. The conductivity of two high-strength and high-conductivity copper alloys by solution pretreatment solution plus drawing pretreatment were both gradually increased with ageing temperature and holding time. The conductivity of Cu-Zr-Te alloy was higher than that of Cu-Zr-Cr alloy by same processes. SEM analysis showed that Zr, Te,Cu intermetallic compound were precipitation , during the aging process ,which resulted in the precipitation hardening.The periodic oxidation property of the high strength and electrical conductivity copper alloys at 400℃and 500℃in air were also examined. The result showed the oxidation resistance of several of the high strength and high conductivity copper alloy was by the order as Cu-Zr-As, Cu-Zr-Cr, Cu-Zr-Te, Cu-Te, Cu-Te-La, Cu. XRD analysis showed that the surface oxidation layers on were composed of Cu_O and CuO. The alloying elements of Zr, Cr, As, and Te can enhance the oxidation resistance of the copper alloys by the different mechanism.Finally, sliding friction and wear Cu-Zr-Te alloy with four kinds of treatment was studied. The result showed that the higher hardness of the Cu-Zr-Te alloy was, the higher its wear resistance was, and the greater the load more serious wears. The sequence of the wear resistance of the Cu-Zr-Te alloy from high to low was as following: solution treatment + cold draw + peak aging, solution treatment + cold draw, solution treatment + peak aging and solution treatment. SEM results showed that there were not only scratch, scar and plough groove but also iron and oxygen elements, which indicated that the wear mechanism of the Cu-Zr-Te alloy is a combination of adhesives, abrasive and oxidation wear. |
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