Effect of the volume fraction of the icosahedral phase on the microstructures, hot compressive behaviors and processing maps of Mg-Zn-Y alloys
- Authors
- Kwak, T. Y.; Lim, H. K.; Kim, W. J.
- Issue Date
- 25-Nov-2017
- Publisher
- ELSEVIER SCIENCE SA
- Keywords
- Metals and alloys; Liquid-solid reactions; Mechanical properties; Microstructure; Quasicrystals
- Citation
- JOURNAL OF ALLOYS AND COMPOUNDS, v.725, pp.711 - 723
- Journal Title
- JOURNAL OF ALLOYS AND COMPOUNDS
- Volume
- 725
- Start Page
- 711
- End Page
- 723
- URI
- https://scholarworks.bwise.kr/hongik/handle/2020.sw.hongik/4970
- DOI
- 10.1016/j.jallcom.2017.07.164
- ISSN
- 0925-8388
- Abstract
- The effect of the volume fraction (0.6-8.4 vol %) of the icosahedral phase (I-phase, Mg3Zn6Y1) on the microstructure, hot deformation mechanism and hot workability of cast Mg-Y-Zn alloys was studied. As the volume fraction of I-phase increased, the fraction of dynamically recrystallized (DRXed) grains increased, indicating that I-phase promoted dynamic recrystallization (DRX) by providing the preferred nucleation sites for DRXed grains through particle stimulated nucleation mechanism. There was, however, a critical amount of I-phase (about 5 vol %) beyond which the fraction of DRXed grains decreased. This was attributed to the formation of relatively coarse divorced eutectic I-phase and lamellar I-phase structures at the volume fraction of I-phase >= 5%. This result indicates that besides the amount of I-phase, the size of I-phase structure is another important factor affecting DRX. Processing maps were constructured to evaluate the hot workability of the alloys with different volume fraction of I-phase. The hot workability increased as the volume fraction of I-phase increased up to about 5 vol % but decreased afterward, confirming that DRX and hot workability are correlated with each other. The hot workability increases with increasing I-phase amount because the occurrence of extensive DRX delays the onset of power-law breakdown and flow instability to higher strain rates and lower temperatures. (C) 2017 Elsevier B.V. All rights reserved.
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Collections - Graduate School > Materials Science and Engineering > 1. Journal Articles
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