薄板曲面微结构电流辅助滚压成形工艺研究
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摘要
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.
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.
引文
[1]穆阿姆梅尔科驰,图格鲁勒欧泽勒.微制造-微型产品的设计与制造[M].于化东,译.北京:国防工业出版社,2016.KOC M,OZEL T. Micro-manufacturing design and manufacturing of micro-products[M]. Translated by YU Huadong. Beijing:National Defense Industry Press,2016.
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[6] XU Z T,PENG L F,FU M W. Size effect affected formability of sheet metals in micro/meso scale plastic deformation:experiment and modeling[J]. International Journal of Plasticity,2015,68:34-54.
[7] SALANDRO W A,JONES J J. Formability of Al 5xxx sheet metals using pulsed current for various heat treatments[J]. Journal of Manufacturing Science and Engineering, 2010, 132(5):051016.
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[9]杜引,赵亦希,于忠奇,等. 2060-T8铝锂合金电致塑性本构方程[J].塑性工程学报,2017,24(1):133-149.DU Yin,ZHAO Yixi,YU Zhongqi,et al. Constitutive equation of electroplastic effect for 2060-T8 Al-Li alloy[J]. Journal of Plasticity Engineering,2017,24(1):133-149.
[10] OERKINS T A,KRONENBERGER T J. Metallic forging using electrical flow as an alternative to warm/hot working[J]. Journal of Manufacturing Science and Engineering,2006,129(1):84-94.
[11] GREEN C R,MCNEAL T A. Springback elimination for Al-6111 alloys using electrically-assisted manufacturing(EAM)[J]. Trans.North Am. Manuf. Res. Inst. SME,2009,37:403-410.
[12] WANG X W,XU J,SHAN D B,et al. Modeling of thermal and mechanical behavior of a magnesium alloy AZ31 during electricallyassisted micro-extrusion[J]. International Journal of Plasticity,2016,85:230-257.
[13] FAN R,MAGARGEE J,HU P,et al. Influence of grain size and grain boundaries on the thermal and mechanical behavior of 70/30brass under electrically-assisted deformation[J]. Materials Science and Engineering:A,2013,574:218-225.
[14] JORDAN A,KINSEY B. Investigation of thermal and mechanical effects during electrically-assisted microbending[J]. Journal of Materials Processing Technology,2015,221; 1-12.
[15] SIOPIS M S,KINSEY B L. Experimental investigation of grain and specimen size effects during electrical-assisted forming[J]. Journal of Manufacturing Science and Engineering,2010,132(2):021004-021004-7.
[16] ZHENG Q,SHIMIZU T,SHIRATORI T,et al. Tensile properties and constitutive model of ultrathin pure titanium foils at elevated temperatures in microforming assisted by resistance heating method[J]. Materials and Design,2014,63:389-397.
[17]杨阳.高频脉冲电流对轧制变形抗力的影响[D].秦皇岛:燕山大学,2012.YANG Yang. The influence of high frequency pulse on the rolling deformation resistance[D]. Qinhuangao:Yanshan University,2012.
[18] FAN R,NG M K,XU D K,et al. Experimental and numerical study of electrically-assisted micro-rolling[J]. AIP Conf. Proc.,2013,1532(1):1038-1043.
[19] GB/T 5231—2012,加工铜及铜合金牌号和化学成分[S].GB/T 5231—2012, Designation and chemical composition of wrought copper and copper alloys[S].
[2] HIRT G,THOME M. Rolling of functional metallic surface structures[J]. CIRP Annals:Manuf. Technol.,2008,57(1):317-320.
[3] LU B,MENG W J. Roll molding of microchannel arrays on Al and Cu sheet metals:a method for high-throughput manufacturing[J]. Journal of Micro-and Nano-Manufacturing,2014,2(1):011007-011007-9.
[4]王传果.板材表面微沟槽滚压成形工艺研究[D].长春:吉林大学,2016.WANG Chuanguo. Study on roll forming grooves on the surface of sheet metal[D]. Changchun:Jilin University,2016.
[5] GAO Z Y,PENG L F,YI P Y,et al. Grain and geometry size effects on plastic deformation in roll-to-plate micro/meso-imprinting process[J]. Journal of Materials Processing Technology,2015,219:28-41.
[6] XU Z T,PENG L F,FU M W. Size effect affected formability of sheet metals in micro/meso scale plastic deformation:experiment and modeling[J]. International Journal of Plasticity,2015,68:34-54.
[7] SALANDRO W A,JONES J J. Formability of Al 5xxx sheet metals using pulsed current for various heat treatments[J]. Journal of Manufacturing Science and Engineering, 2010, 132(5):051016.
[8]李超,王国峰,潘显荣,等.电流辅助高强钢板热成形工艺数值模拟研究[J].精密成形工程,2016,8(5):116-120.LI Chao,WANG Guofeng,PAN Xianrong,et al. Numerical simulation of current assisted hot stamping of high strength steel[J].Netshape Forming Engineering,2016,8(5):116-120.
[9]杜引,赵亦希,于忠奇,等. 2060-T8铝锂合金电致塑性本构方程[J].塑性工程学报,2017,24(1):133-149.DU Yin,ZHAO Yixi,YU Zhongqi,et al. Constitutive equation of electroplastic effect for 2060-T8 Al-Li alloy[J]. Journal of Plasticity Engineering,2017,24(1):133-149.
[10] OERKINS T A,KRONENBERGER T J. Metallic forging using electrical flow as an alternative to warm/hot working[J]. Journal of Manufacturing Science and Engineering,2006,129(1):84-94.
[11] GREEN C R,MCNEAL T A. Springback elimination for Al-6111 alloys using electrically-assisted manufacturing(EAM)[J]. Trans.North Am. Manuf. Res. Inst. SME,2009,37:403-410.
[12] WANG X W,XU J,SHAN D B,et al. Modeling of thermal and mechanical behavior of a magnesium alloy AZ31 during electricallyassisted micro-extrusion[J]. International Journal of Plasticity,2016,85:230-257.
[13] FAN R,MAGARGEE J,HU P,et al. Influence of grain size and grain boundaries on the thermal and mechanical behavior of 70/30brass under electrically-assisted deformation[J]. Materials Science and Engineering:A,2013,574:218-225.
[14] JORDAN A,KINSEY B. Investigation of thermal and mechanical effects during electrically-assisted microbending[J]. Journal of Materials Processing Technology,2015,221; 1-12.
[15] SIOPIS M S,KINSEY B L. Experimental investigation of grain and specimen size effects during electrical-assisted forming[J]. Journal of Manufacturing Science and Engineering,2010,132(2):021004-021004-7.
[16] ZHENG Q,SHIMIZU T,SHIRATORI T,et al. Tensile properties and constitutive model of ultrathin pure titanium foils at elevated temperatures in microforming assisted by resistance heating method[J]. Materials and Design,2014,63:389-397.
[17]杨阳.高频脉冲电流对轧制变形抗力的影响[D].秦皇岛:燕山大学,2012.YANG Yang. The influence of high frequency pulse on the rolling deformation resistance[D]. Qinhuangao:Yanshan University,2012.
[18] FAN R,NG M K,XU D K,et al. Experimental and numerical study of electrically-assisted micro-rolling[J]. AIP Conf. Proc.,2013,1532(1):1038-1043.
[19] GB/T 5231—2012,加工铜及铜合金牌号和化学成分[S].GB/T 5231—2012, Designation and chemical composition of wrought copper and copper alloys[S].