Microstructure development of ultra fine grained Mg-22 wt%Gd alloy prepared by high pressure torsion
SCIE
SCOPUS
- Title
- Microstructure development of ultra fine grained Mg-22 wt%Gd alloy prepared by high pressure torsion
- Authors
- Cizek, J.; Hruska, P.; Vlasak, T.; Vlcek, M.; Janecek, M.; Minarik, P.; Krajnak, T.; Slapakova, M.; Dopita, M.; Kuzel, R.; Kmjec, T.; Kim, J. G.; Kim, H. -S.
- Date Issued
- 2017-09
- Publisher
- ELSEVIER SCIENCE SA
- Abstract
- A hardenable lightweight Mg-22 wt%Gd alloy with ultra fine grained (UFG) structure was prepared by high pressure torsion (HPT) at ambient temperature. The development of microstructure during HPT processing was investigated. A homogeneous UFG structure with grain size of 300 nm was achieved after 15 HPT revolutions. The UFG alloy exhibits enhanced strength due to work strengthening by tangled dislocations forming a dense forest throughout grains. Dislocation density in the sample was determined by positron annihilation spectroscopy (PAS) and X-ray line profile analysis (XLPA). It was found that there is an additional source of X-ray profile broadening in addition to small crystallites and micro-strains caused by dislocations. The additional micro-strain component was attributed to lattice modulation by Gd-rich nano-wires formed by agglomeration of Gd solutes and to strains arising from boundaries of crystallite domains and inter-domain interactions. Analysis of the influence of the crystallite size on the strength of UFG Mg-22 wt%Gd alloy revealed a breakdown in the HallPetch relationship when the crystallite size decreased below a critical value of approximate to 30 nm.
- Keywords
- Y-ZR ALLOY; SEVERE PLASTIC-DEFORMATION; LINE-PROFILE ANALYSIS; HALL-PETCH BREAKDOWN; AZ61 MAGNESIUM ALLOY; MECHANICAL-PROPERTIES; THERMAL-STABILITY; POSITRON-LIFETIME; NANOCRYSTALLINE MATERIALS; UNEXPECTED FORMATION
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/50429
- DOI
- 10.1016/j.msea.2017.07.100
- ISSN
- 0921-5093
- Article Type
- Article
- Citation
- MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, vol. 704, page. 181 - 191, 2017-09
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