The Research Of Hot Deformation Mechanical Behavior And Processing Map Of C919Aluminum Alloy

Abundant aluminum, aluminum lightweight characteristics, making it moreand more in industry occupies an important position, very competitive comparedwith other materials.C919alloy is Al-Zn-Mg-based high-strength aluminumalloy heat treatment can enhance the deformation.Has low density, high strength,thermal processing performance, etc., is a major aerospace structural materials.As a load-bearing structural components in the aerospace, marine, civil andother fields has been developing applications.Cast samples of C919aluminum alloy were used solution heat treatment atdifferent temperature and time, that to analyze on microstucture, the besttechnics of the homogenizing heat treatment of the material is sure. Then, thematerials were tried an experiment in hot compression test withGLEEBLE^-1500thermal simulate testing machine at the strain rate level which is0.001s^-1～1s^-1, and at the deformation temperature level which is350℃～470℃.Analyzing change law of the deformation temperature and strain rate on fiowstress and microstructure established constitutive model of heat deformation ofC919aluminum alloy. Based on processing diaggram theory of dynamicmaterial model, processing diagram of the material can be drawed underdifferent variable conditions. The results of this paper showed that:（1） The non-equilibrium phase of alloy gradually distributed with solutiontemperature increment or expanding holding time, and the grain boundarybecomed thin. After solution treatment, The second phase of alloy completelydissolved into the substrate. And best homogenization technics of C919aluminum alloy is defined which temperature is460℃and holding time16h.（2） Flow stress-strain curve of C919aluminum alloy is characterized bydynamic recovery and recrystallization softening mechanism. The higher thetemperature, the more prone to generate dynamic recrystallization under thecertain strain rate conditions. The low strain rate taked a good effect onhappening to dynamic recrystallization under the certain temperature conditions. Peak stress decreased with the increasing of deformation temperature or thereduction of strain rate.（3） Hot compression rheological behavior of C919aluminum alloy can bedescribed as hyperbolic sine function corrected Arrhenius relation andtemperature compensation deformation rate factor z, which state clearly that thehigh-temperature plastic deformation is controled by heat-activated. Thematerial have four characteristic parameters that stress exponent n=4.73, stressfactor α=0.02Mpa^-1, structure factor A=1.09×106s^-1, deformation activationenergy Q=79.084KJ/mol.（4） By comparing to hot processing diagram of different dependent variable,the result showed that, hot processing paramenters level that deformationtemoerature is350℃～400℃, strain rate is0.001s^-1～0.01s^-1, they taked a goodeffect on the deformation of C919aluminum alloy.