(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 云南冶金集团服份有限公司，昆明 650502；
3. 中南大学 轻合金研究院，长沙 410083；
4. 中南大学 高性能复杂制造国家重点实验室，长沙 410083)
摘 要: 基于四点弯曲变形装置，采用光学金相显微镜(OM)、透射电子显微镜(TEM)等显微表征技术，结合回弹率和室温力学性能测试，研究预拉伸量对2124铝合金蠕变时效成形中回弹与性能同步的影响。结果表明：蠕变时效成形条件下的预拉伸量适用范围与人工时效不同，选择恰当的预拉伸量可实现蠕变时效成形过程中成形目标与材料性能的耦合调控。随着预拉伸量的增加，弯曲板材试样蠕变时效后的回弹率先快速下降后缓慢回升，且在预拉伸3%处，出现回弹最小值；合金的强度呈现出“双峰形”的增长特征，分别在预拉伸2%和5%处达到峰值，在预拉伸3%处，出现极小值；综合考虑2124铝合金板材蠕变成形后的强度、塑性和回弹等条件，推荐的预拉伸量范围为1.5%~2.5%。
关键字: 蠕变时效成形；铝合金；预拉伸；回弹
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Yunnan Metallurgical Group Co., Ltd, Kunming 650502, China;
3. Light Alloy Research Institute, Central South University, Changsha 410083, China;
4. State Key Laboratory of High Performance and Complex Manufacturing, Central South University, Changsha 410083, China）
Abstract:Based on a four-point-bend forming tools, the effect of pre-stretching on the synchronization of springback and mechanical property in creep age forming of 2124 aluminum alloy was investigated by optical microscopy (OM), transmission electron microscopy (TEM), and tests of springback and mechanical property. The results show that choosing a proper pre-deformation can achieve coupling control of the forming target and the material property in creep age forming process. As the pre-stretching degree increasing, the springback decreases firstly, reaches the minimum value at the pre-stretching degree of 3%, and then rises again slowly. And the strength property curves of the 2124 aluminum alloy present a bimodal variation characteristic, the corresponding pre-stretching at the two peak points are 2% and 5%, respectively, and the minimum point exists at pre-streching of 3%. With comprehensive consideration of the mechanical property and the springback, the recommendatory pre-stretching range of the creep age forming of 2124 aluminum alloy sheets is 1.5%-2.5%.
Key words: creep age forming; aluminum alloy; pre-stretching; springback
