Preparation Of High Strength Aluminum Alloy Channel Angular Pressing Organizational Control Study

7003 aluminum alloy is a kind of high-strength aluminum alloy, which possesses fine thermal deformation capacity and processing propertv,fine weldability and fatigue strength.It can automatically aging after welding. In recent years,7003 aluminum alloy has been used more widely in aerospace and automobile industry.7003 aluminum alloy will be better applied in various fields when its performances are improved.SPD(Severe Plastic Deformation) technology is an effective way to improve material strength through grain refinement. The results show that:when the grains of material are refined to 1μm, the material will show a series of unwonted performance in physics, chemistry, and mechanics.Therefore, the grains refinement of aluminum alloy has important theoretical significance and application meaning. There are many methods to prepare ultra-fine grain materials,One of them is Equal Channel Angular Pressing(ECAP).During the ECAP process, materials are severely refined with easy manufacture and low cost.The preparation of superfine crystal materials with superior performance have attracted wide attention in the material world. ECAP method is good application value and prospect.In this experiment, the 7003 aluminum alloy was estruded five passes by ECAP. The microstructures of samples were observed by optical microscope,transmission electron microscope and the X-ray diffraction.It turned out that the crystals of 7003 aluminum alloy were refined obviously with the increase of pass.After five pass of ECAP, grain boundaries had a trend of becoming straight, the average grain size get to 400nm around. Dislocation density increased obviously and formed tangle when the pass of ECAP were increasing.However, it no longer increased but reduced after the forth pass. In the forth pass,Dislocation tangles was turning into tiny subgrain.The pressed material were tested by tensile,compression experiment and microhardness test. It turned out that the mechanical properties of materials improved obviously with the increase of pass.From the initial annealing condition to the forth pass,The tensile strength increase from 336.17 MPa to 405.33Mpa. The yield strength increased from 265.1Mpa to 421.4Mpa.The microhardness increased from 72.8HV to 138.4HV. After ECAP pressing,different recrystallization annealing system was try to the pressed sample, and the regularity of microstructure evolution in different recrystallization annealing technology was analysis.It was found that when anealing at temperature 160℃for 1h,The average grain size of sample does not increase, but trended to have a further refinement.It provided basis for further studies and parameters formulation in industrial production.