利用单点和双点渐进成形技术（SPIF/TPIF）制作了AA1100铝合金金字塔台形工件，通过阳极覆膜、背散射电子衍射技术和透射电镜观察渐进变形前后的微观组织。在台形件的两个成形平面上进行取样，进行室温拉伸实验和维氏硬度测试。实验结果表明：渐进成形后多晶体组织呈现（220）取向。渐进成形时板料表面层晶粒细化机理为位错分割细化，晶粒从原始尺寸11.5 μm细化到1.5 μm，细化后的晶粒多为细小亚晶，渐进成形后材料的屈服强度提高15 MPa以上，材料呈现明显的加工硬化，工具头接触面的硬度提高35%以上。通过比较板材轧制织构与工具头不同运行方向的平面，发现试样横向平面在轧制方向的伸长率明显高于轧向平面的伸长率。相比于单点渐进成形，双点渐进成形后的微观组织更加均匀，加工硬化效果更明显，两者拉伸强度接近。
Abstract
The pyramidal workpieces of AA1100 aluminum alloy were formed by single-point and two-point incremental forming (SPIF/TPIF). The microstructure before and after incremental forming was observed by anodic coating, backscattered electron diffraction technique and transmission electron microscope. The samples were taken from two forming planes of the pyramidal workpiece, the tensile test at room temperature and Vickers hardness test were carried out. The experiment results show that the polycrystalline structure presents (220) orientation after incremental forming. The grain refinement mechanism of the surface layer of sheet during incremental process is dislocation segmentation, and the grain size is refined from 11.5 μm to 1.5 μm, and the refined grains are mostly fine subgrains. After incremental forming, the yield strength of the material increases more than 15 MPa, the material shows obvious working hardening, and the hardness of the tool head contacted surface increases more than 35%. Considering the plane which rolling texture is in different direction with the tool head direction, it is found that the elongation of the transverse plane is significantly higher than that of the rolling plane. Compared with the single point incremental forming, the microstructure of the two-points incremental forming is more uniform and the hardening effect is more obvious, and the tensile strengths of two incremental forming methods are similar.
关键词
AA1100铝合金 /
渐进成形 /
显微组织 /
力学性能
{{custom_keyword}} /
Key words
AA1100 aluminum alloy /
incremental sheet forming /
microstructure /
mechanical property
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] JESWIET J, MICARI F, HIRT G, et al. Asymmetric single point incremental forming of sheet metal[J]. CIRP Annals-Manufacturing Technology, 2005, 54(2):88-114.
[2] XU D K, LU B, CAO T T, et al. Enhancement of process capabilities in electrically-assisted double sided incremental forming[J]. Materials & Design, 2016, 92:268-280.
[3] 王华毕,魏目青,徐旺丁. 变角度缓面零件渐进成形刀具轨迹优化[J].塑性工程学报,2017,24(2):59-63. WANG Huabi,WEI Muqing,XU Wangding. Tool path optimization for variable angle surface parts in single point incremental forming[J]. Journal of Plasticity Engineering,2017,24(2):59-63.
[4] 方进秀,莫健华,崔晓辉,等.铝合金筒形件的电磁脉冲辅助渐进拉深成形[J].塑性工程学报,2016,23(3):58-61. FANG Jinxiu,MO Jianhua,CUI Xiaohui,et al.Electromagnetic pulse assisted incremental deep drawing of aluminum cylindrical cup[J].Journal of Plasticity Engineering, 2016,23(3):58-61.
[5] SILVA M B, SKJOEDT M, ATKINS A G, et al. Single-point incremental forming and formability-failure diagrams[J]. Journal of Strain Analysis for Engineering Design, 2008, 43(1):15-35.
[6] MCANULTY T, JESWIET J, DOOLAN M. Formability in single point incremental forming:A comparative analysis of the state of the art[J]. Cirp Journal of Manufacturing Science & Technology, 2017, 16:43-54.
[7] LIEVERS W B, PILKEY A K, LLOYD D J. Using incre mental forming to calibrate a void nucleation model for automotive aluminum sheet alloys[J]. Acta Materialia, 2004, 52(10):3001-3007.
[8] GB/T 228.1-2010,金属材料拉伸试验第1部分:室温试验方法[S]. GB/T 228.1-2010,Metallic materials-Tensile testing-Part 1:Method of test at room temperature[S].
[9] GB/T 4340.1-2009,金属材料维氏硬度试验第1部分:试验方法[S]. GB/T 4340.1-2009,Metallic materials-vickers hardness test-Part 1:Test method[S].
[10] MONTAZERI-POUR M, PARSA M H, JAFARIAN H R, et al. Microstructural and mechanical properties of AA1100 aluminum processed by multi-axial incremental forging and shearing[J]. Materials Science & Engineering A, 2015, 639:705-716.
[11] PIRGAZI H, AKBARZADEH A, PETROV R, et al. Micro structure evolution and mechanical properties of AA1100 aluminum sheet processed by accumulative roll bonding[J]. Materials Science & Engineering A, 2008, 497(1-2):132-138.
[12] XU P, LUO H, LI S, et al. Enhancing the ductility in the age-hardened aluminum alloy using a gradient nanostructured structure[J]. Materials Science and Engineering:A, 2017, 682:704-713.
[13] KWAN C, WANG Z, KANG S B. Mechanical behavior and microstructural evolution upon annealing of the accumulative roll-bonding (ARB) processed Al alloy 1100[J]. Materials Science and Engineering:A, 2008, 480(1):148-159.
[14] EMMENS W C, VAN DEN BOOGAARD A H. Strain in shear, and material behaviour in incremental forming[J]. Key Engineering Materials, 2007, 344:519-526.
[15] 陈水生,林建平,刘景.AA5182-O铝拼焊板焊缝晶粒尺寸对力学性能的影响[J].塑性工程学报,2016,23(3):68-71. CHEN Shuisheng,LIN Jianping,LIU Jing.Effect of grain size on mechanical properties of AA5182-O aluminum alloy tailor welded blanks[J].Journal of Plasticity Engineering, 2016,23(3):68-71.
[16] PETCH N J. The cleavage strength of polycrystals[J]. J. Iron Steel Inst., 1953, 174(1):25-28.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
基金
国家自然科学基金委员会-中国航天科技集团公司航天先进制造技术研究联合基金资助项目（U1737210）
{{custom_fund}}
PDF(3687 KB)
