Research On Creep Age Forming Behavior Of Aluminium Alloy Friction Stir Welding Components

According to the development trend of the structure that use the whole wall plate instead of traditional assembly structure on modern aircraft fuselages and wing stuctures, puts forward the creep age forming technology of friction stir welding components, it provides new ideas for low cost manufacturing of the whole wall plate. For coruse of the technology is in preliminary process test, the forming mechanism still no system of research. In this paper, based on the new way of idea about aluminum alloy wlole way plate parts on creep age forming of friction stir welding, from the theoretical analysis, process test and microanalysis, carry out the forming mechanism of the limitation of research, to explore the realization process of basis, lay the foundation for the process of engineering application.From the independent design of welding jigs and creep age forming die, complete the processing forming process of2A12aluminium alloy plates, verify the feasibility of the composite technique. For sake of finding the rebound differences, design mold tooling by the theoretical calculation, and have a contrast of welding parts and no-welding parts on the rebound rate. Then, analysis the hardness distribution and intensity change on the welding line features area, get the tensile strength have big enhancement when the friction stir welding plate have a8h creep aging treatment, that friction stir welding forming limitation has certain ascending function to the strength of the panel.By metallographic microscope and scanning electron microscopy, and combined with the macrotest results, have a system research to the microstructure characteristics on aging welding characteristics of the area. The results show that: FSW organization include Weld Nugget (WN), Thermo-mechanically Affected Zone (TMAZ), Heat Affect Zone (HAZ), Base Metal area (BM). The grain of WN is abnormal small because of effects from the dynamic recrystallization phenomenon caused by mechanical agitation. TMAZ, there are certain grain of deformation, after creep aging forming, become more even. Forward side of HAZ are the most vulnerable area between the limitation, the grain of HAZ is too large under the influence of mechanical agitation, and has already overaging before aging, with the aging process, effect of solid solution strengthening and overaging coexist, the regional strength fist increases, then decreases the present trend, there are the best time limitation. At the same time, both aeras of BM and HAZ are elements of the grain boundary segregation phenomenon, rich in Cu. According to the characteristics of the fracture morphology, the fractures after creep age forming are fracture toughness nest, the toughness nest density after creep age forming were significantly more than before the creep age forming, and all the size are increased, the better plasticity.