Study On HFQ Warm Forming Of 7075 Aluminum Alloy Based On Mesoscopic Damage

In recent years, the rapid development of automobile industry has brought enormous energy consumption problem.To produce safe, energy efficient and environmentally friendly automobile has been the subject of the auto industry development.To achieve this goal, the effective method is automotive lightweight technology. On the basis of stable ascending car strength and safety performance reduce the quality of the car, design the light quality and energy security components so as to improve the power performance of vehicle, greatly reduce fuel consumption to meet the demand of the contemporary people to the car. Aluminium alloy has a low density and high strength, and is the ideal of lightweight engineering material.However, using the traditional forming process of aluminum alloy, blanks are easy to springback deformation after forming. On the basis of the traditional warm forming process, there is a new type of aluminum alloy warm forming technology:Solution Heat treatment-Forming-Cold Die Quenching, referred to as HFQ process.On the basis of improving the forming performance of aluminum alloy, it can effectively reduce the forming springback, achieve good mechanical properties.Material forming process starting from the deformation until the damage is a gradual degradation process, material initial damage and internal structure inevitably exist various kinds of defects, such as micro cracks, the existence of defects such as micro holes. GTN mesoscopic damage model considering the material due to the internal damage, the characterization of internal damage evolution of each parameters have clear physical meaning, the GTN mesoscopic damage model is introduced into the sheet metal forming numerical simulation technology, can more effectively help us to study the effect of damage to the material forming. Damage parameters in GTNmodel accurately determine to become one of the key factors on the related research.Around these problems, this paper studied the basic mechanical properties of7075 aluminum alloy, at 25 ℃ to 475 ℃ temperature range, 0.01 s- 1 strain rate under the condition of complete one-way thermal tensile experiment.Through the hot tensile test for basic mechanical properties of materials we will get the basic mechanics performance of data.And use the datas to appliy the simulation software of ABAQUS to establish a single model.Through the way of response surface optimization-genetic algorithm to determine the GTN parameters.In order to obtain accurate mesoscopic damage parameters, in this article,through experiment and numerical simulation method, based on GTN damage model of aluminum alloy are studied under the condition of HFQ technology of warm forming performance.Combination of box deep drawing model was studied the influence of the mesoscopic damage for sheet metal forming. The results show that the initial forming temperature, blank holder force have important influence on the forming.Higher initial forming temperature, effectively improve the formability of7075 aluminum alloy. Under the same temperature, the increase of blank-holder force makes the forming of aluminum alloy significantly reduced. The results of numerical simulation based on GTN model and the experimental results keep the same trend. Related research results of aluminum alloy worm forming performance will provide theoretical support for the subsequent process optimization.