6063 Aluminum Alloy Conductor Rail With Determination Of Ttp Curve And Heat Treatment Technology Was Studied

6063Al alloy is widely used in power supply system of urban rail, because of its favorable properties such as low denity, high corrosion resistance, excellent extruding performance and thermal and electrical conduction performance. By means of hardness testing、electrical conduction testing、room-temperature tensile testing、SEM、TEM、EPMA and DSC tests, TTP curves were determined, and solid solution and ageing treatment of6063Al alloy electric rail profiles was researched in order to improve the tensile strength and electric conductivity of the alloy and provide some heat treatment references for factories simultaneously.The results show that the critical temperature ranges from300to410℃with the nose temperature of about360℃. From TEM analysis, heterogeneous precipitate β-Mg2Si is prior to nucleate on the (AlFeSi) dispersoids in the critical temperature range, and grows up most rapidly at the nose temperature of360℃. The heterogeneous precipitation leads to a low concentration of solute, which consequently reduces the amount of the strengthening phase after aging. This phenomenon indicates that, in the large-scale industrial production of6063aluminum alloy, the cooling rate during quenching should be slowed down properly from the solution temperature to410℃; then it should be enhanced as high as possible in the quench sensitive temperature range (410～300℃) to suppress the heterogeneous precipitation; while below300℃, it should be slowed down again to get optimal mechanical properties. The burning temperature of6063Al alloy is540℃; the solid solubility of the alloy is at the most after solution treatment at515℃for70min. Two-step heat treatments improve conductivty a little, but have serious negative effect on strength, so there is no need for Al alloy conductive rail to use two-step heatment. In150～180℃low temperature single-ageing treatment, with the increasing of aging time,6063Al alloy has not overaging phenomenon; and the stable conductivity rises up with the increasing of aging temperature, but the stable strength reduces. In195～240℃high temperature single-ageing treatment, with the increasing of aging time,6063Al alloy exists a peak strength. The time taken to the maximum strength decreased and the corresponding maximum strength decreased with increasing of aging temperature, resulting in a big loss of strength, but the conductivity continue to increase with the increasing of aging time, and the stable conductivity increases remarkable with the increasing of aging temperature. In order to acquire high strength and electrical conductivity composite properties, it is better to age at205235℃. Stay time on the quenched alloy is sensitive, and its mechanical and physical properties change a lot in2h of the delay ageing time. The stay time should be properly control in the actual industry process.