Effect Of Ultrasonic Vibration On Ageing Forming Of 7075 Tailored Blanks

The use of overall panels is increasingly in line with the needs of aircraft manufacturing today,It can effectively reduce the number of parts in aircraft manufacturing,to save manufacturing costs and improve the overall performance of the aircraft.Aging forming technology provides an effective way for the forming and manufacturing of this kind of wallboard.Aiming at the problems of low material utilization and high equipment dependence in aging forming of traditional milling wallboard.The friction stir welding component of 7075 aluminum alloy is studied in this paper,the effect of ultrasonic vibration aging on aging forming performance of7075 aluminum alloy welded sheet was investigated.The researches show that,ultrasonic vibration aging temperature is 200 ?,the welding plate component forming the best effect,is the minimum rebound rate of the whole ultrasonic vibration aging temperature process,its value is 44.83%,the tensile strength decreases with the increase of vibration aging temperature.The ultrasonic vibration was applied for 12 hours,the rebound rate is 49.84%,which is 20.45% lower than that of conventional aging forming,the tensile strength decreases first and then rises as the ultrasonic vibration application time increases,when the ultrasonic vibration was applied for 10 h,the minimum tensile strength was 319.22 MPa.Ultrasonic vibration aging temperature and ultrasonic vibration application time have little effect on the elongation of tailor welded blank members,and the fluctuation value is maintained between 3% and 4%.The overall hardness of 7075 aluminum alloy welded plate decreases with the increase of ultrasonic vibration aging temperature,and the hardness peak decreases and tends to be uniform.The application time of ultrasonic vibration has little effect on the hardness of 7075 aluminum alloy welded plate.The microstructure evolution of 7075 aluminum alloy welded plate by ultrasonic vibration aging process was studied,the ultrasonic vibration aging temperature has coarsening effect on the grains in different welding zones of 7075 aluminum alloy welded plate,the black second phase particles increase with the increase of aging temperature,as the ultrasonic vibration aging temperature increases,the shape of the dimple is flatter.Ultrasonic vibration application time has little effect on grain size,the evolution of black second phase particles is similar to the ultrasonic vibration agingtemperature,the longer the ultrasonic vibration application time,the smaller the size and number of the fractured dimples,and the tearing ridges first decrease and then increase,ultrasonic vibration can promote the transformation of GP region and intermediate phase ? ? into stable phase ?.The content of stable ? phase increases first and then decreases as the ultrasonic vibration aging time increases.When the stable phase ?grows to a certain size,applying ultrasonic vibration will promote the decomposition of the stable phase ?,the stable ? phase at the grain boundary is continuously refined before applying ultrasonic vibration for 10 h and also becomes a more continuous distribution,when the ultrasonic vibration application time exceeds 10 h,the stable ?phase at the grain boundary grows up,there is no effect on the precipitation boundary of the grain boundary.