Research On Microstructure Evolution And Deformation Behavior Of High Strength Aluminum Alloy

7 series aluminum alloy with low density, high toughness, excellent mechanical properties, excellent processing and welding, especially with high strength, rigidity, elastic modulus ratio, is widely used in the manufacture of aircraft parts and engineer equipment such as tanks, armored vehicles, war vehicles, ships and automobiles, ships and other transportation industry requirements lightweight important materials. At present, the 7 series aluminum alloy mainly uses forging technology to process, the deformation resistance is bigger, the processing cost is high, the efficiency is low, and the machining quantity is too big resources waste is serious, limits its application potential. The near net forming of high strength aluminum alloy with high strength deformation by semi solid forming technology can greatly improve the forming efficiency and resource utilization, and widen the application range.While traditional Sima deformation quantity is limited, not for the subsequent heat treatment to provide enough strain induced, so the plastic deformation by High-Pressure Torsion (HPT) method to replace traditional Sima in cold and hot plastic deformation prepared with nearly globose, fine and homogeneous particles of 7A60 aluminum alloy semi solid billets; study the pressure torsion circle number, semi solid processing temperature and heat preservation time of semi-solid billet microstructure effects, and by SEM and energy spectrum line scan analysis of semi solid processing temperature and holding time on the distribution of the main alloy elements are studied. Research shows that:the transpressional 4～6 laps, isothermal temperature for 580℃ to 600℃, holding 20min, ideal 7A60 semi solid billets can be prepared; with semi solid processing temperature increased or the holding time prolonged, elemental Al matrix and strengthen the elements mg, Zn tends to uniform distribution, Cu gradually to the grain boundary segregation; in the grain boundary segregation of low melting point phase mainly by Cu elements constitute.7A60 aluminum alloy semi solid state thermal simulation compression experiment, explores the thermal compression really should change characteristics of the stress strain curve and the curve data established peak stress constitutive model, the true should stress strain curve fitting. The results show that the 7A60 aluminum alloy semi solid state deformation behavior can be divided into:hardening period, resistance to deformation and lower segment and stable flow section, and flow stress withdeformation temperature increasing or should strain rate decreasing small; in the semi-solid deformation temperature range peak should force model of average relative error is 3.92%, after fitting calculation stress value of the discrete points and the flow stress and strain and the average relative error is 4.38%.The through the above a series of research methods to solve the problem early 7A60 aluminum alloy semi solid forming technology, for high strength deformed aluminum alloy semi solid thixo forming technology development and application of laid a solid theoretical and experimental basis.