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By using OP,SEM,double arm direct electric bridge, electronic universal material testing machine and electric heating high temperature drying box instrument. The effect of Er on the properties and microstructures of Al-Zr-B alloy electric conductors was studied. The results show that additive Er can refine the grain of the alloy, increase the strength of the alloy and heat resistance and conductivity after a reasonable heat treatment. Er can react with impurity elements existing in aluminum matrix to form precipitated phase, thereby the effect of impurity elements on the conductivity of aluminum was reduced, their corresponding the electric conductivity and tensile strength improved. When the Al-0.2Zr-0.06B-0.2Er alloy soaked in the temperature of 220°C for 8h, its tensile strength and equivalent conductivity is 218MPa and 59.8%IACS respectively. The complicated properties of Al-Zr resistant alloy wires are improved, this study is of significance. Introduction Electric power is the indispensable important energy of national economic development. With the rapid development of economic in our country, the demand for power is greatly increased. Sources of Electricity in our country are mostly concentrated in the west region, but the power needed in the eastern region. So large-scale electric powers must be transmitted with long distance from western china to the eastern, exchange of electric power between south and north and interconnection in the whole country has high demands for wires with saving energy, heat resistance and freeze-proofing. High strength heat resistant aluminum alloy wires with high electric conductivity were used to meet the increase of overhead conductors. However, the resistivity of heat resistant aluminum alloy conductor is too high to fit for the electric power long-distance transmission, so development of high strength with high conductivity heat resistant aluminum alloy wire has become a major task in our country[1-2]. Studies have shown that adding suitable amount of Zr element can effectively improve the recrystallization temperature of aluminum and increase the heat resistance of aluminum. Al-Zr alloy conductors with low content of Zr are not fit for strength requirement for long distance electric power transmission. With the increase of content of Zr, the strength of Al-Zr alloy conductors can be increased with electric conductivity of heat-resistant alloy wire decreased rapidly. It is reported that Er can refine the grain and restrain recrystallization of aluminum alloy[3-6], reduce the effect of impurity elements on conductivity of aluminum substrate, then improved the electrical conductivity. Experiments showed that adds the right amount of Zr and B elements at the same time can improve the thermal stability and electrical conductivity of aluminum alloy wire[7]. Al-Zr-B-Er alloy was selected as experimental electric conductive material in this study, followed by continuous ECAE process. It is hoped to find a new method to produce high electrical conductivity -strength Al-Zr resistant heat aluminum alloy conductor. The Experimental Materials and Methods 99.7% industrial pure aluminum is used in experiment, its chemical composition as shown in Tab.1. Al-Zr-B-Er alloy was preparing by adding Al-5%Zr, Al-3B% and Al-20Er master alloys, the mass fraction of Er in the alloy were 0, 0.1, 0.2 and 0.3 respectively. Crucible furnace is used in this experiment to melt aluminum alloy. Firstly, the temperature of the crucible was preheated to International Conference on Material Science and Application (ICMSA 2015) © 2015. The authors Published by Atlantis Press 552 730°Cwith half an hour holding to make the crucible dry, and then industrial pure aluminum was put in clean crucible to be melted completely, then Al-5%Zr master alloy, Al-3%B master alloy and Al-20Er alloy added one by one with each melted completely. After degassed by using nitrogen, slag was removed, and impurity removed. When the temperature reach to 730°C, l iquid alloy were poured into the steel die to produce aluminum alloy bars with water-cooled. After then the bars were homogenized with soaking temperature 510°C for 6h.Then square samples with a cross section of 12mmx12mm and length of 60mm alloy rods were extruded by using homogeneous bars. Finally, the square bars were extruded by using continuous ECAE extrusion die with the BC path, the samples were prepared by 3 passes, 4 passes and 5 passes respectively. Specimens observed by using optical microscope and scanning electron microscopy (SEM). the resistance of the samples wrer measured by Using SB2230 type dc digital resistance tester, then it is converted to electrical conductivity of 20°C. the tensile strength of the sample with the extrusion of 4 passes by using SANS CMT5105 testing machine with tensile speed 30 mm/min. Using the JCT-1 type high temperature electric heating oven insulate sample for 1h, the annealing temperature is 230°C,to test the tensile strength of samples under the high temperature and then calculate the survival rate of intensity of the samples. Tab.1 Chemical composition of Al99.70 industrial purity aluminum ingot(Wt,%) Experimental Results and Analysis The Influence of Extrusion Times to Al-Zr-B Alloy Grain with the Continuous ECAE The microstructures of the Al-Zr-B-Er alloy prepared by different ECAE extrusion passes are shown in Fig.1. It can be seen that their grain size decrease with the ECAE forming passes increase, the homogeneity of the grain increase with the ECAE forming passing increase, equiaxed grains of alloy can be obtained by using 4-pass ECAE forming process. The main reason is that the material was seriously sheared by multi-pass EEAE to provide enough energy, so the secondary recrystallization and grain growth can easy occur. (a) 2 passes; (b) 3 passes; (c) 4 passes; (d) 5 passes Fig.1 The microstructures of the Al-Zr-B-Er alloy prepared by different ECAE extrusion passes Element Si Fe Cu Mg Cr+Mn+V+Ti Al Content 0.08 0.13 <0.05 <0.05 <0.022 Bal.

Influence of Er on Microstructure and Properties of Al-0.2%Zr-0.06%B Heat-resistant Alloy Conductor Prepared by Continuous ECAE Forming