基于细观损伤的7075铝合金HFQ温热成形性能研究
发布时间：2019-05-17 05:37
【摘要】：近年来,汽车行业的飞速发展带来了能源大量消耗的问题。生产出安全且节能环保型汽车成为了汽车产业发展的主题。实现这一目标的有效方法之一是汽车轻量化技术。在确保稳定提升汽车强度和安全性能的基础上最大限度的减轻汽车的质量,设计出质量轻且节能安全的零部件从而提高汽车的动力性,极大的减轻燃料的消耗以满足当代人们对汽车的要求。铝合金材料密度低,比强度高,是理想的轻质工程材料。然而,运用传统的铝合金温成形工艺,样件成形后容易产生回弹变形。因此在传统的温成形工艺基础上,出现了新型的铝合金温成形技术,即温热成形-淬火一体化工艺(Solution Heat treatment-Forming-Cold Die Quenching),简称HFQ成形技术。该工艺在提高铝合金成形性能的基础上,可以有效降低成形件回弹,获得较好的力学性能。材料成形过程中从变形开始直至破坏是一个逐渐劣化的过程,材料内部结构不可避免地存在初始损伤和各种缺陷,例如微裂纹、微孔洞的等缺陷的存在。由于GTN细观损伤模型考虑了材料内部的损伤,其表征材料内部损伤演化的各个参数都具有明确的物理涵义,将GTN细观损伤模型引入到金属板材数值成形仿真技术中,可以更有效的帮助我们研究损伤对于材料成形的影响。GTN模型中损伤参数的准确确定成为了相关研究的关键因素之一。围绕上述问题,本文首先对7075铝合金的基本力学性能进行了研究,在25℃-475℃温度范围内,0.01s-1应变速率条件下完成单向热力拉伸实验。通过热拉伸试验获取材料的基本力学性能。将获得的基本力学性能数据整理并应用到基于GTN模型的ABAQUS仿真软件中建立单拉模型。采用单向拉伸数值模拟—响应曲面优化—遗传算法确定GTN参数。为了获取准确的细观损伤参数,本文通过实验和数值仿真的方法,研究了基于GTN损伤模型的铝合金板材在HFQ工艺条件下的温热成形性能。结合深冲盒模具研究了细观损伤对于板材成形性能的影响。结果表明:初始成形温度、压边力都对成形有重要的影响。升高初始成形温度,有效的改善了7075铝合金的成形性能。在相同温度下,压边力的增大使得铝合金的成形性能显著降低。基于GTN模型的数值仿真结果与实际实验结果趋势相同。相关研究成果可为后续的铝合金温成形性能数值仿真研究及工艺优化提供理论支撑。
[Abstract]:In recent years, the rapid development of the automobile industry has brought about a large number of energy consumption problems. The production of safe, energy-saving and environment-friendly cars has become the theme of the development of the automobile industry. One of the effective ways to achieve this goal is automobile lightweight technology. On the basis of ensuring the stable improvement of the strength and safety performance of the vehicle, the quality of the vehicle can be reduced to the greatest extent, and the light weight and energy saving and safe parts are designed to improve the power performance of the automobile. Greatly reduce fuel consumption to meet the requirements of contemporary people for cars. Aluminum alloy is an ideal lightweight engineering material because of its low density and high specific strength. However, by using the traditional warm forming process of aluminum alloy, the springback deformation is easy to occur after the sample is formed. Therefore, on the basis of the traditional warm forming process, a new type of thermoforming technology for aluminum alloy has emerged, that is, the integrated warm forming and quenching process (Solution Heat treatment-Forming-Cold Die Quenching), referred to as HFQ forming technology. On the basis of improving the formability of aluminum alloy, this process can effectively reduce the springback of forming parts and obtain better mechanical properties. In the process of material forming, it is a gradual deterioration process from the beginning of deformation to the destruction. The internal structure of the material inevitably has initial damage and various defects, such as microcracks, micropores and so on. Because the GTN meso-damage model takes into account the internal damage of the material, and each parameter describing the damage evolution of the material has a clear physical meaning, the GTN meso-damage model is introduced into the numerical forming simulation technology of sheet metal. It can help us to study the effect of damage on material forming more effectively. The accurate determination of damage parameters in GTN model has become one of the key factors in related research. Focusing on the above problems, the basic mechanical properties of 7075 aluminum alloy were studied in this paper. The unidirectional thermal tensile test was completed in the temperature range of 25 鈩，
本文编号：2478846
[Abstract]:In recent years, the rapid development of the automobile industry has brought about a large number of energy consumption problems. The production of safe, energy-saving and environment-friendly cars has become the theme of the development of the automobile industry. One of the effective ways to achieve this goal is automobile lightweight technology. On the basis of ensuring the stable improvement of the strength and safety performance of the vehicle, the quality of the vehicle can be reduced to the greatest extent, and the light weight and energy saving and safe parts are designed to improve the power performance of the automobile. Greatly reduce fuel consumption to meet the requirements of contemporary people for cars. Aluminum alloy is an ideal lightweight engineering material because of its low density and high specific strength. However, by using the traditional warm forming process of aluminum alloy, the springback deformation is easy to occur after the sample is formed. Therefore, on the basis of the traditional warm forming process, a new type of thermoforming technology for aluminum alloy has emerged, that is, the integrated warm forming and quenching process (Solution Heat treatment-Forming-Cold Die Quenching), referred to as HFQ forming technology. On the basis of improving the formability of aluminum alloy, this process can effectively reduce the springback of forming parts and obtain better mechanical properties. In the process of material forming, it is a gradual deterioration process from the beginning of deformation to the destruction. The internal structure of the material inevitably has initial damage and various defects, such as microcracks, micropores and so on. Because the GTN meso-damage model takes into account the internal damage of the material, and each parameter describing the damage evolution of the material has a clear physical meaning, the GTN meso-damage model is introduced into the numerical forming simulation technology of sheet metal. It can help us to study the effect of damage on material forming more effectively. The accurate determination of damage parameters in GTN model has become one of the key factors in related research. Focusing on the above problems, the basic mechanical properties of 7075 aluminum alloy were studied in this paper. The unidirectional thermal tensile test was completed in the temperature range of 25 鈩，
本文编号：2478846
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