Influence Of Grain Refinement And Heat Treatment On Microstructure And Mechanical Properties Of6082Aluminum Alloy Tube

Abstract:6082aluminum alloy is widely used in rail transportation、 electric power chemical and other industries.The aim of this thesis was to research the influence of different grain refining agent, different homogenization processe, different online quenching and aging processes on microstructure and properties of6082aluminum alloy tube. The main conclusions of this thesis are as follows:(1) The greater the number and the smaller of the TiAl3and TiB2, the potato-like shape of the particle, the better of the grain refinement; the distribution of TiAl3and TiB2more uniform obtain the better grain refinement; the way of existence of Ti on grain refinement is greater than the content of Ti.(2)For6082aluminum alloy, the homogenization temperature below540℃have no apparent homogenization effect; for12h at560℃, grain boundary becomes tiny and uniform, thick black Mg2Si phase completely disappeared, the homogenization process is the best; for4h at590℃, supersaturated crystalline phase was dissolved in a very short period of time, the Mg2Si phase growth overly, melt into the intergranular, shape like dumbbell, microstructure become overburnt.(3)Microstructure of6082aluminum alloy after online wind quenching process is bigger than water quenching process,mechanical properties is lower than the water quenched alloy, the mechanical performance are difference between13%-22%.(4)The online quenching process of6082aluminum alloy was used the water quenching, with the aging time increased, tensile strength is increased first and then decreased, under the temperature of165℃,175℃,185℃respectively in10hours,6hours,4hours would reach the maximum intensity360Mpa, continue to extend the time of heat preservation will lead to the tensile strength decrease,185℃×4h is the best aging processes.