BOSS FORMABILITY OF A ZR-BASED BULK METALLIC GLASS
SCIE
SCOPUS
- Title
- BOSS FORMABILITY OF A ZR-BASED BULK METALLIC GLASS
- Authors
- Jun, HJ; Lee, KS; Chang, YW
- Date Issued
- 2009-06
- Publisher
- ELSEVIER SCI LTD
- Abstract
- Macroscopic solid-to-solid hot formability of a Zr-based bulk metallic glass has been investigated in this study by applying a boss forming process within supercooled liquid region (SLR). The morphology and microstructures after boss forming were first examined by using an optical microscopy (OM), a field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM). The variation of thermal properties before and after boss forming was also analyzed by using a differential scanning calorimeter (DSC). The glass transition temperature, T-g and the crystallization onset temperature, T-x, onset were found to decrease with increasing test time and temperature. Macroscopic extrusion formability was found to match well with the results predicted through a processing map based on a dynamic materials model (DMM). The specimens were found to form well under the conditions of high temperature and slow punch jig speed. A FEM simulation study has also been carried out to understand the causes of piping problem. A sound boss without a pipe could be formed by reducing the flow rate difference in the contact and the core sites. (C) 2008 Elsevier Ltd. All rights reserved.
- Keywords
- Bulk metallic glass; Mechanical properties at high temperatures; Boss forming; Crystallization; UNDERCOOLED LIQUID-STATE; STRUCTURAL RELAXATION; MECHANICAL-PROPERTIES; DEFORMATION-BEHAVIOR; AMORPHOUS-ALLOYS; FLOW; NANOCRYSTALLIZATION; CRYSTALLIZATION; PHASE
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/28534
- DOI
- 10.1016/j.intermet.2008.12.007
- ISSN
- 0966-9795
- Article Type
- Article
- Citation
- INTERMETALLICS, vol. 17, no. 6, page. 463 - 470, 2009-06
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