基于宏微耦合的铝合金板材零件低残余应力热成形机理研究

项目名称： 基于宏微耦合的铝合金板材零件低残余应力热成形机理研究

项目编号： No.51205143

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 机械工程学科

项目作者： 邓磊

作者单位： 华中科技大学

项目金额： 25万元

中文摘要： 铝合金板材零件的残余应力相对于屈服强度所占比重较大，容易引起大幅度蠕变变形，严重影响尺寸精度和使用寿命。本项目基于微观组织影响弹性回复性能这一实践结果，提出一种基于宏微耦合的残余应力降低方法。在板材热弯曲变形完成后通过控制冲头温度和凹模温度以及模内保温时间，在零件的变形区域形成沿板厚方向的梯度温度分布和梯度微观组织分布，获得所需要的弹性回复性能，进而实现低残余应力分布。 项目将通过物理实验和理论推导，深入研究热力学工艺条件对铝合金微观组织演化以及微观组织对弹性回复的影响规律，揭示宏观变形和微观冶金行为综合作用下残余应力变化的机理，建立考虑应变状态的残余应力模型；利用有限元数值模拟方法研究工艺条件对热弯曲V形支梁残余应力的影响规律，并通过V形支梁热弯曲成形试验验证所提方法的正确性，得出工艺参数优化设计的原则，为实现V形支梁等对残余应力要求高的航空航天零件低残余应力成形奠定理论与实验基础。

中文关键词： 铝合金板材；残余应力；热成形；微观组织演化；宏微耦合

英文摘要： Compared to yield strength of aluminium alloy sheet, the percentage of residual stress in sheet part is very large and easy to cause large scale creep behaviour, which has a serious effect on dimensional accuracy and operating life. According to the research results of literatures that the microstructure plays an important role in springback, a new method considering macro-micro coupling is proposed to decrease residual stress. Through control punch temperature, die temperature and holding time, gradual temperature and gradual microstructure can be obtained in deformation zone after hot sheet bending. If the gradual distribution is reasonable to satisfy the needed springback property, the residual stress will decrease. The physical simulation experiment and theory deduction will be employed to study the effect of thermal-mechanical conditions on microstructure evolution and the effect of microstructure on springback property. The mechanism of residual stress change induced by plastic deformation and metallurgical behaviour also will be investigated, and then the residual stress model considering different strain states will be established. The finite element numerical simulation will be carried out to study the effect of technological parameters on residual stress of a bened V-shpae beam. Finally, the process te

英文关键词： Aluminium alloy sheet；Residual stress；Hot forming；Microstructure evolution；Macro-micro coupling