Study On Microstructure And Microstructure And Properties Of Ultrafine Grain Aluminum Alloy Prepared By Double Channel Equal Channel Angular Pressing

Severe Plastic Deformation (SPD) is one of the effective methods to improve the strength of materials. The study shows that the rain size was obviously refined and the strength was improved in the process of the SPD. The grains can be refined to less than1u m after SPD at the same time, and the ultra-fine grain material can be prepared. Double Equal Channel Angular Pressing (DECAP) as one of the SPD process method, can refine the grain size strongly to prepare the ultra-fine grain material.DECAP was proposed to prepared7003Al alloy ultrafine grain, The microstructure of the deformation was observed by Metallographic microscope,Transmission electron microscopy (TEM), and X-ray diffraction (XRD). Simultaneously, the impact of extrusion deformation on microstructure and properties was analyzed through tensile test,hardness and corrosion testing.Research results show that(1)After four passes extrusion deformation, The grain size of7003aluminum alloy was refined from21μm to0.3μm, the ultra-fine grain7003aluminum alloy was prepared Successfully.(2)In the process of extrusion deformation, there is a lot of dislocation in the sample with the strength and hardness has increased. The hardness, yield strength and tensile strength of four times deformation sample were significantly improved to61.6%,203.4%and155%, and the elongation of specimen decreased by20%to15.8%.(3)The corrosion test showed that:there is no significant difference among pitting corrosion properties of7003aluminum alloy.(4) In the process of annealing, the specimen of deformation occur reply recrystallization with increasing annealing temperature and holding time. Result, the specimen of deformation appears softening with the strength and hardness reduced.