Effect Of Cryogenic Multidirectional Forging On Microstructure And Properties Of 2219 Aluminum Alloy And Process Test

2219 aluminum alloy has excellent casting properties and welding performance,and is the main structural material of transition ring of carrier rocket tank.However,the copper content of 2219 aluminum alloy exceeds the limit of solid solubility of aluminum matrix,and the microstructure evolution is complex during forming and heat treatment,which brings great challenges to high performance manufacturing of ring.Team made in previous studies have found that conventional heating ring problems such as crystal phase and residual bulky fibrous tissue,leading to mechanical performance is not up to standard and three to the performance difference are significant.The high temperature large rheology and middle temperature ring rolling process,refine the grain size ring organization,improve the mechanical properties of the ring,but there is still a local tissue inhomogeneous,anisotropic obvious problems.To this,this paper proposes a cryogenic coordinated regulation of multidirectional forging and heat treatment of 2219 aluminum alloy organization performance of new ideas and research under the condition of extreme manufacturing residual crystallization phase and grain organization evolution,and its effect on the performance of three-way and uniformity,providing theoretical basis for high performance manufacturing ring and experimental basis,the main research work is as follows:(1)The evolution of residual crystalline phase and grain structure of2219 aluminum alloy at different deformation temperature and amount was studied.Under the extreme condition of deep cold deformation,the degree of breakage of coarse crystalline phase is obviously enhanced,and the dissolution diffusion is more sufficient in the subsequent heat treatment process,and the size of residual crystalline phase is obviously refined.However,with the increase of deformation degree,the residual crystalline phase has local segregation phenomenon.When the temperature is-196℃and the deformation degree is 20%,the residual crystalline phase is fine and uniform.The grain size decreased from 105μm to 33μm when the temperature was-196℃ and the deformation degree was 20%.(2)The effect of cryogenic multidirectional forging on microstructure and mechanical properties of 2219 aluminum alloy was studied.Cryoscopic multidirectional forging enhances the effect of residual crystallization phase dissolution,recrystallization grain refinement and deformation uniformity.Different microstructure and properties are more uniform.The area fraction of the residual crystallization phase is reduced to 0.36%,the grain size is refined to 19μm,the tensile strength and yield strength are increased by 20-30 MPa,and the elongation of the central part is increased by about 20%(3%).However,the effect of microstructure refinement and performance improvement is not obvious with the increase of multidirectional forging passes from three to six.(3)Physical simulation experiments on cryogenic forming of 2219 aluminum alloy ring were carried out.Effectively reduce the size of microstructure and improve the uniformity of microstructure;The area fraction of the residual crystallization phase decreases from 1.01% to0.43%,the grain size decreases from 150μm to 80μm,and the size of the main strengthening phase θ ’decreases about 20 nm.Under the new process,the triaxial properties and their uniformity are significantly improved,in which the tensile strength,yield strength and elongation are increased by40 MPa,10Map and 3.30%,respectively.The IPA value of elongation anisotropy is reduced from 39.2% to 5.5% under the existing process.