Deformation Behavior of Electrically-assisted Micro-tension in Ultrafine-grained Magnesium Alloy

doi:10.3901/JME.2022.16.068

Abstract

Abstract: Aiming at the problems of poor plasticity and low forming accuracy of traditional coarse-grained magnesium alloy materials, a novel electrically-assisted (EA) micro-forming method is proposed using ultrafine-grained (UFG) magnesium alloy. The UFG magnesium alloy with an average grain size of ~110 nm were prepared using high-pressure torsion (HPT). The deformation behavior of electrically-assisted micro-tension using coarse-grained (CG) and UFG samples were studied respectively. The results indicate that the flow stress of both CG and UFG magnesium alloy decreases obviously when applying currents. Compared with CG magnesium alloy, the UFG magnesium alloy exhibits lower tensile strength and higher elongation under the same conditions. The results of fracture morphology observation show that there are obvious differences between CG and UFG magnesium alloy. The deformation of the CG magnesium alloy is uneven and the partial fusing occurs after ductile fracture, while the deformation of UFG magnesium alloy is more uniform, and the overall fusing occurs after the formation of cracks from the outer surface of the sample. On this basis, an EA micro-forming thermal processing map of UFG magnesium alloy was constructed. The results show that UFG magnesium alloy has higher power dissipation efficiency and its forming performance is significantly better than that of CG magnesium alloy.

Key words: micro-forming, electroplasticity, ultrafine grains, high-pressure torsion, magnesium alloy

CLC Number:

TG146

YU Jun, CHEN Wanji, XU Jie, SHAN Debin, GUO Bin. Deformation Behavior of Electrically-assisted Micro-tension in Ultrafine-grained Magnesium Alloy[J]. Journal of Mechanical Engineering, 2022, 58(16): 68-76.

References

[1] QIN Y, BROCKETT A, MA Y, et al. Micro-manufacturing: Research, technology outcomes and development issues[J]. International Journal of Advanced Manufacturing Technology, 2010, 47(9-12): 821-837.
[2] BAO Jianxing, XU Jie, QU Jiazheng, et al. Electrically- assisted micro-forming process of gear structure in TA15 titanium alloy[J]. Journal of Mechanical Engineering, 2021, 57(1): 210-216. 包建兴, 徐杰, 曲家正, 等. TA15钛合金齿轮结构电流辅助微成形工艺研究[J]. 机械工程学报, 2021, 57(1): 210-216.
[3] ZHAO Jingwei, WANG Tao, JIA Fanghui, et al. Experimental investigation on micro deep drawing of stainless steel foils with different microstructural characteristics[J]. Chinese Journal of Mechanical Engineering, 2021, 34(2): 189-199.
[4] CHAN W L, FU M W. Studies of the interactive effect of specimen and grain sizes on the plastic deformation behavior in microforming[J]. International Journal of Advanced Manufacturing Technology, 2012, 62(9-12): 989-1000.
[5] GUO Dongming, LU Yongfeng. Overview of extreme manufacturing[J]. International Journal of Extreme Manufacturing, 2019, 1(2): 9.
[6] VOLLERTSEN F, BIERMANN D, HANSEN H N, et al. Size effects in manufacturing of metallic components[J]. CIRP Annals Manufacturing Technology, 2009, 58(2): 566-587.
[7] VALIEV R Z, ISLAMGALIEV R K, ALEXANDROV I V. Bulk nanostructured matetials from severe plastic deformation[J]. Progress in Materials Science, 2000, 45(2): 103-189.
[8] SABBAGHIANRAD S, KAWASAKI M, LANGDON T G. Microstructural evolution and the mechanical properties of an aluminum alloy processed by high-pressure torsion[J]. Journal of Materials Science, 2012, 47(22): 7789-7795.
[9] WANG C T, GAO N, WOOD R, et al. Wear behavior of an aluminum alloy processed by equal-channel angular pressing[J]. Journal of Materials Science, 2011, 46(1): 123-130
[10] MA E. Instability and ductility of nanocrystalline and ultrafine-grained metals[J]. Scripta Materials, 2003, 49(7): 663-668.
[11] HUANG Y, LANGDON T G. Advances in ultrafine-grained materials[J]. Materials Today, 2013, 16(3): 85-93.
[12] VALIEV R Z, LANGDON T G. Principles of equal-channel angular pressing as a processing tool for grain refinement[J]. Progress in Materials Science, 2006, 51(7): 881-981.
[13] ZHILYAEV A P, LANGDON T G. Using high-pressure torsion for metal processing: Fundamentals and applications[J]. Progress in Materials Science, 2008, 53(6): 893-979.
[14] SALANDRO W A, JONES J J, MCNEAL T A, et al. Formability of Al 5xxx sheet metals using pulsed current for various heat treatments[J]. Journal of Manufacturing Science and Engineering, 2010, 132(5): 051016
[15] SPRECHER A F, MANNAN S L, CONRAD H. Overview no. 49: On the mechanisms for the electroplastic effect in metals[J]. Acta Metallurgica, 1986, 34 (7): 1145-1162.
[16] JONES J J, MEARS L, ROTH J T. Electrically-assisted forming of magnesium AZ31: Effect of current magnitude and deformation rate on forgeability[J]. Journal of Manufacturing Science and Engineering, 2012, 134(3): 034504.
[17] SIOPIS M S, KINSEY B L, KOTA N, et al. Effect of severe prior deformation on electrical-assisted compression of copper specimens[J]. Journal of Manufacturing Science and Engineering, 2011, 133(6): 064502.
[18] STOLYAROV V V. Deformability and nanostructuring of Ti Ni shape-memory alloys during electroplastic rolling[J]. Materials Science and Engineering: A, 2009, 503(1): 18-20.
[19] MAI J M, PENG L F, LAI X M, et al. Electrical-assisted embossing process for fabrication of micro-channels on 316L stainless steel plate[J]. Journal of Materials Processing Technology, 2013, 213 (2): 314-321.
[20] PERKINS T A, KRONENBERGER T J, ROTH J T. Metallic forging using electrical flow as an alternative to warm/hot working[J]. Journal of Manufacturing Science and Engineering, 2007, 129(1): 84-94.
[21] OKAZAKI K, KAGAWA M, CONRAD H. A study of the electroplastic effect in metals[J]. Scripta Metallurgica, 1978, 12 (11): 1063-1068.
[22] SPRECHER A F, MANNAN S L, CONRAD H. Overview no. 49: On the mechanisms for the electroplastic effect in metals[J]. Acta Metallurgica, 1986, 34(7): 1145-1162
[23] ZENG Z, STANFORD N, DAVIES C, et al. Magnesium extrusion alloys: A review of developments and prospects[J]. International Material Review, 2018, 64 (1): 27-62.