Effect Of Static Electric Field On The Creep Age Forming Of 7075 Aluminum Alloys

The creep age forming(CAE) is a new developed technology that in order to solve the problem of aircraft integral panel forming,and In the future it have broad application prospects to the aerospace industry.The traditional CAE process is mainly discussed in the research of temperature field and stress field on the formability. Based on the 7075 high strength aluminum alloy of aircraft as the research object, this paper will introduce high voltage electrostatic field in CAE treatment of the alloy. After the treatment of CAE and solid solution treatment both in different intensity of electric field(STEF) for the 7075 aluminum alloys, to research the influence of the limitation of alloy forming, and respectively compared to normal CAE treatment and general solid solution treatment with electric field, analysising of mechanical properties, microstructure of the alloy. This study extends the study of 7075 aluminum alloy of CAE, and provides a new way of thinking to the research of CAE.In order to conduct the experimental research on the electric field CAE, design and prepare a good insulation aging forming tooling. And using two pieces of stainless steel plate as an electrode and makeing an electric field solution equipment, which can be well complete solid solution treatment experiment of 7075 aluminum alloy sheets. Using self-made testing apparatus to carry out the test of 7075 aluminum alloy with the electric field CAE tratment and the electric field CAE after STEF, and discussing the technical parameters the influence of the specimen on the spring rate, the microstructure and mechanical properties. In particular, analyzes the mechanism of electric field of aluminum alloy.The results show that applying an electric field in the aging forming process of 7075 aluminum alloy, can promote the stress relaxation, improve the forming rate of alloy, and with the increase of electric field intensity the effect better; Applying an electric field intensity ascend to a certain extent, but not significant; The electric field CAE compared to normal aging forming treatment on the alloy’s hardness and elongation basically have no effect. Electric field within the 7075 aluminum alloy solid solution treatment can accelerate the diffusion of alloying elements, become the more formation of supersaturated solid solution, so that after the electric field CAE treatment the second phase precipitation increased more dispersion and distribution. Compared to the treatment of the electric field CAE after general solid solution, with the augmentation of the electric field, the treatment of the electric field CAE after STEF can certainly extent reduce the resilient rate of alloy, but has little influence on the strength of the alloy. By comparing the electric field CAE, the electric field CAE after STEF is more advantageous to alloy strength increase, and the overall hardness value than electric field aging forming; At the same time, the electric field CAE after STEF have more apparent influence on tensile elongation of the specimens, and the largest elongation rate reached 17.12%, more than the general solid solution after elongation increased by 3.82%. Approved by the SEM analysis of specimen with the electric field CAE treatment after STEF,the tensile fracture more toughness than the electric field CAE treatmen after general solid solution, and the distribution is more even, that suggest the plasticity of alloy is improved.