Achieving high strength and ductility in magnesium alloys via densely hierarchical double contraction nanotwins.

Fu, Hui; Ge, Bincheng; Xin, Yunchang; Wu, Ruizhi; Fernandez, Carlos; Huang, Jianyu; Peng, Qiuming

Abstract

Light-weight magnesium alloys with high strength are especially desirable for the applications in transportation, aerospace, electronic components, and implants owing to their high stiffness, abundant raw materials, and environmental friendliness. Unfortunately, conventional strengthening methods mainly involve the formation of internal defects, in which particles and grain boundaries prohibit dislocation motion as well as compromise ductility invariably. Herein, we report a novel strategy for simultaneously achieving high specific yield strength (∼160 kN m kg-1) and good elongation (∼23.6%) in a duplex magnesium alloy containing 8 wt % lithium at room temperature, based on the introduction of densely hierarchical {1011}-{101 1} double contraction nanotwins (DCTWs) and full-coherent hexagonal close-packed (hcp) particles in twin boundaries by ultrahigh pressure technique. These hierarchical nanoscaled DCTWs with stable interface characteristics not only bestow a large fraction of twin interface but also form interlaced continuous grids, hindering possible dislocation motions. Meanwhile, orderly aggregated particles offer supplemental pinning effect for overcoming latent softening roles of twin interface movement and detwinning process. The processes lead to a concomitant but unusual situation where double contraction twinning strengthens rather than weakens magnesium alloys. Those cutting-edge results provide underlying insights toward designing alternative and more innovative hcp-type structural materials with superior mechanical properties.

Citation

FU, H., GE, B., XIN, Y., WU, R., FERNANDEZ, C., HUANG, J. and PENG, Q. 2017. Achieving high strength and ductility in magnesium alloys via densely hierarchical double contraction nanotwins. Nano letters [online], 17(10), pages 6117-6124. Available from: https://doi.org/10.1021/acs.nanolett.7b02641

• Journal Article Type: Article
• Acceptance Date: Aug 31, 2017
• Online Publication Date: Aug 31, 2017
• Publication Date: Oct 11, 2017
• Deposit Date: Nov 2, 2017
• Publicly Available Date: Sep 1, 2018
• Journal: Nano letters
• Print ISSN: 1530-6984
• Electronic ISSN: 1530-6992
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 17
• Issue: 10
• Pages: 6117-6124
• DOI: https://doi.org/10.1021/acs.nanolett.7b02641
• Keywords: Double contraction twinning; MgLi alloy; Nano twins; Ultrahigh pressure
• Public URL: http://hdl.handle.net/10059/2571