Research Of Deformation Strengthening And Toughening Behavior And Mechanism Of Spray Forming7055Aluminum

Because of its excellent properties, ultra-high-strength aluminum alloy which is formingby spray forming technology is widely used in the aerospace and other manufacturingindustries. But there are a large number of pores in billet alloy deposition organization ofspray forming process, in addition to this, other shortcomings are also be found, such as lowintensity, and poor plasticity. Further These defects hinder its development and application.Seeking reasonable processing and heat treatment system is considered to be an effective wayto improve the mechanical properties of ultra-high-strength aluminum alloy.In this paper, spray forming7055aluminum alloy is used as the research object, usingoptical microscopy analysis (OM), X-ray scanning analysis (XRD), differential thermalanalysis (DSC), testing of tensile properties and hardness. a single-stage solid-solution systemand single-stage aging system of spray forming7055aluminum alloy, the effect of thermostatrepeatedly changed shape and Heat Treatment on deposited and microstructure tissue andmechanical properties have be studied, it provides a theoretical basis for the alloy processing.The contents are as follows:Microstructure of spray forming7055aluminum alloy is equiaxed grains, the size ofgrain which is mainly composed of α-Al phase and MgZn2phase is about50μm, The tensilestrength of alloy is105Mpa.After repeated deformation heated at400℃, Alloy becomes denseand tensile strength is improved significantly, Up to375MPa. With increasing frequencydistortion, in turn increases the tensile strength of the alloy.In heat treatment study. Deformation alloysolid solution and aging treatment at differenttemperatures and times. The alloy have best effect of solid solution when it stay in480℃for3hours(hardening).Then,the alloy will have the best mechanical properties when it stay in 120℃for20hours(air cooling).The grains of alloy become small and some strengtheningphase which is MgZn2phase separate out.So the line of the alloy heat treating is identified:480℃×3h (hardening)+120℃×20h (air cooled).After thermostat repeatedly changed shape alloy is be overheating treatment which is480℃×3h (hardening)+120℃×20h (air-cooled), the size of alloy grain decreases. A lot ofstrengthening phase is precipitation. Mechanical properties of the alloy are improved greatly.With the increase in the number deformation in turn increases the mechanical properties of thealloy. The tensile strength and hardness can be up to620MPa and90.3HRB. Elongation of itis4.5%.