| The thick plates of Al-Zn-Mg-Cu aluminum alloys with high strength and toughness are indispensable key structural materials in the modern aerospace, aviation, military equipment and civilian facilities. Due to the poor plastic, it is difficult for Al-Zn-Mg-Cu aluminum alloys to realize large deformation above 95% in thermoplastic molding process, so traditional processing method can not obtain sufficient deformation under the condition of the existing equipment, and it is difficult to realize refinement and uniformity of the aluminum alloy plate. Multi-way Forging (MF) makes the loads of deformation process change; such generates large deformation at the same time to prevents the texture. It has widely application prospect since it is unnecessary to power and special equipment.Concerning a new aluminum alloy of Al-Zn-Mg-Cu with high performance, this paper researches the property of thermal deflection, the influence to deformation of upsetting and pulling and the influence to re-crystallization of particle in matrix. Optimize Multi-way Forging (MF) of the thick plates of Al-Zn-Mg-Cu aluminum alloys at last. The procedures and results in the research are represented following:1. The deformation process of Al-Zn-Mg-Cu alloy is simulated with Gleeble-1500D Thermal simulator. The evolution rule of organization in the temperature range of 250℃～420℃and the rate of deformation from 0.01s-1 to 1s-1 and the deformation range 20%～80% is studied. The optimal processing parameters are obtained finally to provide theoretical support for Multi-way Forging (MF).2. With the different deformation mode of upsetting and drawing out of high-strength aluminum alloy, study the influence of microstructure evolution regularity in thermal deformation process. The result shows that the same deformation can lead to the strain values of deformation low, and the effect of the organization thinning is not obvious. However the drawing out can get the stain value high and also get the strains distribution uniformity. The microstructure change obviously. The results provide theoretical basis for multiplex forging process of upsetting and the ratio distribution of drawing out.3. Under the second grains, research the re-crystallization influence of the Al-Zn-Mg-Cu high strength aluminum alloy. Due to the size of particles can rise more than 1um particle inspire nucleation so as to promote the role of re-crystallization, simultaneously must meet the particle inspire nucleation criterion Fv/r < 0.2, so designed the 470℃/ 2h solid solution + 400℃/ 8h and 400℃(8h,10h,12h,14h,16h), direct aging exhalation satisfying conditions of two large size particles, comparing experiment scheme comparison results show that 400℃+ 12h when the second phase particles meet the limitation of the criterion, particle inspire nucleation and total about 1um particle peak particle percentage. Will heat treatment after upsetting samples after the contrast that 50% of 400℃+ 12h organization under the limitation of the most refined, so make sure that the best heat treatment system is 400℃+ 12h.4. According to the heat treatment system 400℃+ 12h has been determined, forging temperature is 400℃, strain rate 0.01 per second and drawing out ratio was greater than upsetting ration ,under the deformation mode of drawing out ratio more than upsetting ratio, the multi-way forging process are optimized for the Al-Zn-Mg-Cu high strength aluminum alloy plate. Deform simulation results show that the strain of the sample heart can be achieved 11.85, and the minimum strain on edges place is about 8.21 ~ 8.86, most regions'equivalent strain is more than 9.68 and distribution in comparison even. The actual size aluminum alloy plate in southwest aluminum success in the trial, and the various performances achieve the use requirement. |
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