Research On Rare Earth Microalloyed High Conductivity,Heat-Resistant Aluminum Alloy Materials And Wear Properties

The conductivity of heat-resistant aluminum alloy wires on overhead transmission lines is ? 60% IACS(20?),which is 1% IACS lower than that of ACSR made of hard aluminum conductor materials,and it leads to 1.5% increase in line losses.This leads to the failure for large area applications of heat-resistant aluminum alloy wires.Therefore,the key to the development of heat-resistant aluminum wire is improving the conductivity of heat-resistant aluminum alloy to reduce transmission line losses with a higher current capacity at the same time.Simultaneously,during the operation of the overhead wire,the ice and wind speed will cause vibration,the resulting fretting wear behavior will damage the aluminum alloy material.Based on the problems above,we hope to obtain the ideal heat-resistant aluminum alloy conductor alloy system and its preparation process by studying the effect of micro-alloying to the microstructure,heat-resistant mechanism and fretting wear behavior of aluminum conductor.In this paper,the heat-resistant aluminum alloy was chosen as the object of study,and the research aims at high-conductivity and heat-resistant aluminum alloy based on microalloying which towards the low conductivity of heat-resistant aluminum alloy wire,the mismatch of heat resistance,mechanical properties and electrical properties,the serious problem of fretting wear.The main research content and the results are as follows:(1)Al-Zr alloy was chosen as the main research material,and reavealed the regulation rules of micro-alloying elements Zr,B,rare earth elements to the property by adding rare earth elements Er or Y.At the same time,it solved the matching design problems between micro-alloying formula of aluminum alloy and properties.(2)The strengthening mechanism of different second phases in the heat-resistant aluminum alloy wire was studied systematically.The mechanism of the second phase configuration on the macroscopic properties of the electrical aluminum alloy was proposed and verified.The addition of Zr and Re microalloying elements.The optimum composition of the heat-resistant aluminum alloy conductor was optimized,and the composition formula of 61% IACS high-conductivity heat-resistant aluminum alloy conductor material was obtained finally.(3)The results of high temperature aging test,tensile test at room temperature and electrical conductivity test on the new microalloyed high-conductivity heat-resistant aluminum alloy monofilament wire show that the microstructure of the wire is refined by designing the multi-microalloying to ensure a high initial strength and plasticity.The wire has good short-term softening resistance and long-term softening resistance at 120 ° C.Precipitation containing Zr and Er during the aging process improves the heat resistance while improving the conductivity of the wire.(4)The friction and wear tests of two kinds of heat-resistant aluminum alloy were carried out with different grease.The surface morphology and composition of the abrasive grains were analyzed.The results showed that the new grease had higher thermal stability at 2HZ and 5HZ than that of the traditional composite grease with better friction and wear resistance.