薄板曲面微结构电流辅助滚压成形工艺研究

Electrically-assisted rolling process of curved thin foil micro-features

针对燃料电池等系统中的薄板曲面微结构制造,提出了薄板曲面微结构滚压成形工艺,并借助电流辅助成形技术,提高了薄板曲面微结构的成形质量。采用单向拉伸实验,研究了脉冲电源参数如电压、频率、脉宽等对T2紫铜薄板单向拉伸变形行为的影响;开展了薄板曲面微结构滚压变形有限元模拟,优化坯料结构,抑制了曲面微结构件的翘曲失稳;在此基础上,开展了电流辅助滚压成形实验。结果表明,脉冲电流在达到一定阈值时,流动应力显著降低,断裂应变明显提高;采用梯形板坯,可优化板料受力状态,抑制翘曲失稳;脉冲电流辅助滚压成形时,曲面微结构高度分散性变小,成形件一致性更好,微结构尺寸精度更高。

To manufacture curved thin foil micro-features used in fuel cell,a kind of rolling process was utilized,and electrically-assisted forming technology was introduced to improve the forming quality of curved micro-features.Using the uniaxial extension test,effects of parameters of pulse power on deformation behaviors,such as voltage,frequency and pulse width,were investigated.The FE simulation for rolling process of curved thin foil micro-features was performed,and the sheet shape was optimized to inhibit the warping instability.Then,electrically-assisted rolling tests were carried out.Experimental results show that flow stress decreases obviously,and fracture strain increases clearly when the pulse power increases to the threshold value.Ladder type of the sheet can inhibit the warping by optimizing stress states.With the electrical power,the scatter of height of curved micro-feature becomes smaller,which means that the homogeneity of formed features can be improved obviously.Besides,the dimensional accuracy of the micro-feature becomes higher.