Study On Rare Earth Aluminum Alloy Conductor Material Of High-performance

With the development of our economy, our electric power system as well asthe large-scale infrastructure construction, the domestic demand for wire and cableis growing rapidly. At present the most adopted cable conductor material is copperconductor. However since copper is scarce resources in China and copper has arelatively high price, the material costs of copper cable take up more than70%ofthe total cable costs. If we use pure aluminum conductor material, based on theexperience of using it in China, after it is being used for a long time or are currentoverload, a large creep will occur, which leads to the increasing contact resistanceand possibility of accidents. The bending performance is not good since thematerial is easy to crack or break and is prone to accident as well. Therefore, thestudy of the aluminum alloy conductor material is imperative.In this paper, the orthogonal test program is adopted. Using the self-hardeningresin sand casting, rotary forging process, prepare the rare earth aluminum alloyrod; test the tensile strength, elongation at break and conductivity, study the effectof alloying elements of iron, copper, magnesium and cerium on the mechanicalproperties and electrical conductivity of rare earth aluminum alloy conductormaterial, in order to obtain an optimum formula which has the high conductivityand good mechanical properties of the rare earth aluminum alloy conductormaterial. The results show that: tensile strength of rare earth aluminum alloyconductor material keeps increasing as the content of iron, copper, magnesium andrare earth elements cerium increases. The effect by iron on the tensile strength isthe largest, followed by magnesium, copper, and cerium. As the content of iron ormagnesium increases, the elongation at break of rare earth aluminum alloyconductor material decreases, which is affected mostly by iron. Add0.10%to0.40%copper in the rare earth aluminum alloy conductor material: as the content ofcopper increases, elongation at break of rare earth aluminum alloy conductormaterial first increases and then decreases. With relatively small changes in value,the copper element is shown to have little impact on the elongation at break of rareearth aluminum alloy conductor material. Add0.10%to0.30%rare earth elementcerium in the rare earth aluminum alloy conductor material. When the content ofrare earth element cerium is more than0.1%and less than0.2%, with the increase of cerium, elongation at break decreases; while when the content is more than0.2%and less than0.3%, as the element content increases, elongation at breakcontinuously improves; the conductivity of rare earth aluminum alloy conductormaterial keeps reducing as the content of iron, copper and magnesium increases.The conductivity is mostly affected by iron of, followed by magnesium, copper.The conductivity of rare earth aluminum alloy conductor material is improved withthe increase of the content of rare earth element cerium. Considering test resultsand practical applications of the rare earth aluminum conductor materialrequirements for mechanical properties and conductivity, the best alloycomposition would be:0.25%Fe,0.40%Cu,0.05%Mg,0.30%Ce,0.008%B, the restfor aluminum and unavoidable impurities.After determining the best alloy element composition ratio of rare earthaluminum alloy conductor material, through continuous casting and rolling anddrawing, prepare rare earth aluminum alloy wire of alloy elements compositionwith the best ratio. Carry out annealing treatments under different parameters onthe rare earth aluminum alloy wire; test the tensile strength, elongation at break,resistivity and conductivity; study the effect of annealing treatment on themechanical properties and electrical conductivity of rare earth aluminum alloy wire.The results show that: annealing treatment will reduce the tensile strength of rareearth aluminum alloy wire and improve the elongation at break, when annealingtemperature stays the same, as the holding time increases, the tensile strength ofrare earth aluminum alloy wire gradually goes down and elongation at break goesup; when holding time remains the same, as the annealing temperature increases,the tensile strength of rare earth aluminum alloy wire gradually decreases andelongation at break increases; when the annealing temperature （in a certain range）and holding time both reach a certain value, whether the annealing temperature orholding time increases, the tensile strength and elongation at break will not havemuch change. The annealing treatment will reduce the resistivity of rare earthaluminum alloy wire and improve the conductivity. When the annealingtemperature stays the same, with the increase of holding time, the resistivity of rareearth aluminum alloy wire gradually goes down and conductivity goes up; whenholding time keeps the same, with the increase of annealing temperature, theresistivity of rare earth aluminum alloy wire gradually decreases and conductivityincreases; Considering experimental results and the practical application of wirecable core on the mechanical properties and electrical conductivity of aluminumalloy conductor requirements, the best process parameters for annealing treatment are: annealing temperature of310℃, with the holding time of30min, direct air cool,the tensile strength of aluminum conductor processed of129N/mm², and theelongation at break, resistivity, and conductivity are15.0%,2.782×10^-8Ω·m and62%IACS respectively.