Effect Of Ultrasonic Vibration On The Creep Age Forming Of 7075 Aluminum Alloys

With the improvement of the maneuverability and high speed for the modern aircraft,the structural design of the aircraft is changing from the traditional riveting assembly to the integral panel structure.However,the creep age forming(CAF)technology which is the effective technique to ensure the integral panel forming quality and improve service life.In China,there are many researches on the CAF technology were under the temperature field and stress field,however,the basic research on the effect of ultrasonic on the CAF is less.This paper takes 7075 Aluminum Alloy as the research object,the effect of ultrasonic vibration on the aging performance of the specimens was studied,which provided a new method for aging forming.In order to study the effect of ultrasonic vibration on the aging performance of specimens,based on ultrasonic vibration device of the self-made,designed and prepared forming tooling aging,the tooling can be safe,stable and effective application of ultrasonic vibration,provided the basic conditions for the influence of specimen forming properties on the aging research of ultrasonic vibration the.In order to obtain the condition of the minimum rebound rate of the specimen after aging forming.Ultrasonic power,ultrasonic time and applied applied the width of the specimen size and other parameters on the effect of resilience was studied by orthogonal test method.The results show that: the order of the influence degree of each factor on the rebound rate of the sample is: ultrasonic time,ultrasonic power,plate width.When the applied ultrasonic power of 1600 W,ultrasonic application time is 12 h,the specimen rebound rate reached minimum;Compared with the normal age forming ultrasonic vibration aging specimen rebound rate decreased by 11.07%;The specimen strength and elongation rate has little effect on the aging forming ultrasonic vibration,the fluctuation value of not more than 4%.In order to better explain the effect of ultrasonic vibration on the formability of aging,but also the use of a variety of micro analysis methods(such as OM,SEM and TEM)were observed and analyzed on microstructure forming ultrasonic vibration aging specimen.The microstructure analysis showed that:Compared with the conventional CAF,The treatment of Ultrasonic vibration has little effect on the grain size of the samples.However,With the increase of ultrasonic time and ultrasonic power,the number and size of the second phase of the structure decrease gradually.The number ofdimples increased gradually,the dimple depth increased,and the dimple size decreased.The precipitates is composed of fine spherical precipitates gradually transformed into lamellar or rod like equilibrium phase,and equilibrium phase size has decrease trend.The shape of the grain boundary precipitate phase is changed from the large particle to the small needle bar,and the spacing of the grain boundary precipitates gradually becomes larger.Grain boundary precipitate free zone has a wider trend with the increase of ultrasonic time and ultrasonic power.Based on the experimental results,the effect of ultrasonic vibration on the aging property of 7075 aluminum alloy was obtained.This provides experimental data reference for the new method,and has certain engineering application value.