The Research On The Limitation Of 6156 Aluminium Alloy Thermal Deformation And Creep

The age-hardenable6156aluminum alloy, which have high strength and low density, have been widely used in aerospace industry.6156aluminum alloy, as for the large aircraft fuselage panel material, the processing technique and the panels manufacturing technology has rarely been reported. The characteristics of properties and microstructure of6156A1alloy under conditions of artificial aging (AA) and creep aging (CA) and its deformation mechanism at a high temperature were studied by using the techniques of optical microscopy (OM), transmission electron microscopy (TEM), Vicker hardness test, tensile properties test, intergranular corrosion test and electric conductivity test. The main conclusions can be drawn as following:(1) The flow stress model of6156aluminum alloy was established. The6156aluminum alloy are showed steady-state rheological characteristics significantly during hot deformation. FHF function model would be best described by optimizing the material constant a value during deformation. The apparent activation energy of hot deformation is240.87kJ/mol. The flow-stress constitutive equation could be expressed as following: ε=4.90×1014[sinh(0.0243·σ)]5.37exp(-240870/RT)(2) The processing map was drawn at the true strain of0.9during hot deformation. The alloy has a good machinability, and its instability due to local rheological are only emerged in partly of the high Z zone. The power dissipation efficiency (η) increased gradually from high Z zone to low Z zone, it reached the highest value(about34%) at the hot deformation condition500℃/1s-1.(3)The microstructure and mechanical properties of6156Al alloy under creep aging were revealed. Compared to artificial aging samples, the creep aging samples have much more and much smaller precipitates, and its mechanical property, electrical conductivity and corrosion resistance are increased. A good thermal stability are maintained during creep aging and its coordination effect of the formation and property is obvious which is suitable for components creep aging forming.(4) The creep behavior of6156aluminum alloy under creep aging was studied. The creep activation energy is152.43kJ/mol and its stress exponent is4.51at the temperature155℃～175℃. The creep is mainly controlled by dislocation climb under the high-stress and it is mainly controlled by diffusion of atoms and vacancies under the low-stress.