High ductility of a bi-modal Mg-7wt.%Y alloy at low temperature prepared by high pressure boriding and semi-solid extrusion. (15th February 2016)

• Record Type: Journal Article
• Authors: Fu, Hui; Li, Hui; Fang, Daqing; Cai, Xuecheng; Peng, Qiuming
• Is Part Of: Materials & design. Volume 92(2016)
• Page Start: 240
• Page End: 245
• Publication Date: 2016-02-15
• Subjects: Mg-Y alloys -- Mechanical properties -- Microstructure -- Texture; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2015.12.024
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: A bi-modal Mg-7wt.%Y alloy has been successfully prepared by a novel route of high pressure boriding and semi-solid extrusion. It reveals superplasticity at a temperature of ~ 170 °C at the strain rate of 1 × 10 − 3 s − 1 . The grain size ranges from hundreds nanometer to 150 μm, wherein the fine grains provide good strength in terms of Hall–Petch relationship, while the coarse grains offer high ductility due to high dislocation storage efficiency. Compared with conventional single fine or coarse grains, this bi-modal structure is confirmed as a more effective pathway in promoting the deformability of Mg alloys because of the occurrence of extension twinning, the presence of large angle grain boundaries and stable nano-scale YB12 particles with a high melting point. Graphical abstract: Highlights: A Mg-7Y alloy was prepared by high pressure boriding and semi-solid extrusion. The novel Mg-7Y alloy has a unique bi-modal structure. An ultrahigh elongation of ~ 38.5% was attained at room temperature. Superplasticity was achieved at ~ 170 °C at the strain rate of 1 × 10 − 3 s − 1 .