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Warming forming, or the combination of cold forming, and multiple heat treatment processes are usually used to obtain AA7075 parts in T6 temper. However, the above-mentioned methods increase the forming cycle and cost, and lead easily to change in the microstructure. In this paper, a new forming process is proposed, namely pure electroplastic-assisted thermal forming (PEPATF) process, which can reduce the forming temperature by using pure electroplastic/non-thermal effect to compensate plasticity loss caused by the decrease of temperature. In order to research the mechanism of electroplastic effect, oven-heating uniaxial tension at different temperatures and electrically assisted uniaxial tension test at different temperatures and current densities are performed for AA7075-T6. On the one hand, the results show that at the same temperature, the flow stress obtained by electrically assisted heating is lower than that obtained by oven-heating, indicating that pure electroplasticity exists and is more obvious with the increase of temperature. Moreover, at the same temperature, the flow stress decreases with the increase of current density at the same temperature. On the other hand, the elongation obtained by electrically assisted uniaxial tension is higher than that obtained by oven-heating uniaxial tension. For electrically assisted uniaxial tension, the largest elongation is at 150 °C.

With the current increasing emphasis on issues of energy saving, emission reduction, driver and passenger safety in automotive industry, lightweight bodywork is an effective measure to reduce vehicle energy consumption. And also, high-strength bodywork structure can improve automobile safety performance because of its high impact absorption energy, and high fatigue resistance. In sheet metal forming, springback is a main defect with using high strength steel. Aiming to investigate sheet metal springback phenomenon for high-strength steel, a multi-funtional springback test machine is built. The testing machine can perform four types of springback tests: V-bend, U-bend, stretchbend and drawbend, and all these tests have been carried out to investgate the effect of springback factor in sheet metal forming processes for example forming speed. The research found that the springback angle of U-bend and drawbend increase with enlarging speed, however, V-bend and stretchbend show the opposite trend.

Titanium alloys are important aerospace materials due to excellent comprehensive performance, but it is difficult to form at room temperature. Electrically assisted hot stretch forming is used to form the titanium panels of aircraft. This paper studies the effect of temperature, strain, stress relaxation time and cooling rate on forming accuracy by stress relaxation test, tensile test and forming experiment. It is shown that for the influence of temperature on forming accuracy, there is no large difference among 773K, 873K, 973K. And with increase of strain, the forming accuracy becomes lower. For the influence of stress relaxation time, there is no large difference among 0min, 15mins, 30mins. And with decrease of cooling rate, the forming accuracy is improved significantly. It’s concluded that when the temperature reaches a high level, temperature and stress relaxation time have no great influence on forming accuracy. And the forming accuracy is mainly influenced by strain and cooling rate. Electrically assisted hot stretch forming is an effective method to form titanium alloy. And the part with high forming accuracy can be obtained by adopting high temperature, low strain, proper stress relaxation time and low cooling rate.