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Title: Development of mechanical properties in a CaO added AZ31 magnesium alloy processed by equal-channel angular pressing

Abstract

Processing through the application of equal-channel angular pressing (ECAP) is recognized as one of the attractive severe plastic deformation techniques where the processed bulk metals generally achieve ultrafine-grained microstructure leading to improved physical characteristics and mechanical properties. Magnesium has received much attention to date for its lightweight, high strength and excellent elasticity. Mg alloys with addition of CaO is reported to provide the successful casting procedure without usage of greenhouse gas, SF{sub 6}, whereas it is generally used for preventing the oxidation of Mg during casting. In the present investigation, a CaO added AZ31 (AZ31-CaO) magnesium alloy was processed by ECAP at elevated temepratures with a few steps of reduction which result in significant grain refinement to ~ 1.5 μm after 6 passes. Compression testing at room temperature demonstrated the AZ31-CaO alloy after ECAP showed enhanced yield strength more than the as-processed commercial AZ31 alloy while both alloys maintained ductility in spite of significant reduction in grain size. The improved strength in the AZ31-CaO alloy was attributed to the formation of fine Al{sub 2}Ca precipitates which experience breaking-up through ECAP and accelerate the microstructural refinement. Moreover, the preservation of ductility was attributed to the enhancement of strain hardening capability inmore » the AZ31 alloy at room temperature. This study discusses the feasibility of using ECAP to improve both strength and ductility on magnesium alloys by applying the diagram describing the paradox of strength and ductility. - Highlights: • AZ31 and AZ31-CaO magnesium alloys were processed by ECAP up to 6 passes. • AZ31-CaO alloy after ECAP showed improved yield strength without losing ductility. • CaO in AZ31 forms fine Al{sub 2}Ca accelerating microstructural refinement during ECAP. • Feasibility of using ECAP was shown to improve both strength and ductility in Mg.« less

Authors:
 [1]; ; ;  [2];  [1]
  1. Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)
  2. Metal Forming Technology R&D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22587097
Resource Type:
Journal Article
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 112; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-5803
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALCIUM OXIDES; CASTING; CASTINGS; DUCTILITY; ELASTICITY; GRAIN REFINEMENT; GRAIN SIZE; MAGNESIUM ALLOYS; PLASTICITY; PRECIPITATION; PRESSING; STRAIN HARDENING; STRAINS; YIELD STRENGTH

Citation Formats

Bae, Seong-Hwan, Metal Forming Technology R&D Group, Korea Institute of Industrial Technology, Incheon 406-840, Jung, Ki Ho, Shin, Young-Chul, Yoon, Duk Jae, Kawasaki, Megumi, and Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453. Development of mechanical properties in a CaO added AZ31 magnesium alloy processed by equal-channel angular pressing. United States: N. p., 2016. Web. doi:10.1016/J.MATCHAR.2015.12.009.
Bae, Seong-Hwan, Metal Forming Technology R&D Group, Korea Institute of Industrial Technology, Incheon 406-840, Jung, Ki Ho, Shin, Young-Chul, Yoon, Duk Jae, Kawasaki, Megumi, & Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453. Development of mechanical properties in a CaO added AZ31 magnesium alloy processed by equal-channel angular pressing. United States. doi:10.1016/J.MATCHAR.2015.12.009.
Bae, Seong-Hwan, Metal Forming Technology R&D Group, Korea Institute of Industrial Technology, Incheon 406-840, Jung, Ki Ho, Shin, Young-Chul, Yoon, Duk Jae, Kawasaki, Megumi, and Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453. Mon . "Development of mechanical properties in a CaO added AZ31 magnesium alloy processed by equal-channel angular pressing". United States. doi:10.1016/J.MATCHAR.2015.12.009.
@article{osti_22587097,
title = {Development of mechanical properties in a CaO added AZ31 magnesium alloy processed by equal-channel angular pressing},
author = {Bae, Seong-Hwan and Metal Forming Technology R&D Group, Korea Institute of Industrial Technology, Incheon 406-840 and Jung, Ki Ho and Shin, Young-Chul and Yoon, Duk Jae and Kawasaki, Megumi and Departments of Aerospace & Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453},
abstractNote = {Processing through the application of equal-channel angular pressing (ECAP) is recognized as one of the attractive severe plastic deformation techniques where the processed bulk metals generally achieve ultrafine-grained microstructure leading to improved physical characteristics and mechanical properties. Magnesium has received much attention to date for its lightweight, high strength and excellent elasticity. Mg alloys with addition of CaO is reported to provide the successful casting procedure without usage of greenhouse gas, SF{sub 6}, whereas it is generally used for preventing the oxidation of Mg during casting. In the present investigation, a CaO added AZ31 (AZ31-CaO) magnesium alloy was processed by ECAP at elevated temepratures with a few steps of reduction which result in significant grain refinement to ~ 1.5 μm after 6 passes. Compression testing at room temperature demonstrated the AZ31-CaO alloy after ECAP showed enhanced yield strength more than the as-processed commercial AZ31 alloy while both alloys maintained ductility in spite of significant reduction in grain size. The improved strength in the AZ31-CaO alloy was attributed to the formation of fine Al{sub 2}Ca precipitates which experience breaking-up through ECAP and accelerate the microstructural refinement. Moreover, the preservation of ductility was attributed to the enhancement of strain hardening capability in the AZ31 alloy at room temperature. This study discusses the feasibility of using ECAP to improve both strength and ductility on magnesium alloys by applying the diagram describing the paradox of strength and ductility. - Highlights: • AZ31 and AZ31-CaO magnesium alloys were processed by ECAP up to 6 passes. • AZ31-CaO alloy after ECAP showed improved yield strength without losing ductility. • CaO in AZ31 forms fine Al{sub 2}Ca accelerating microstructural refinement during ECAP. • Feasibility of using ECAP was shown to improve both strength and ductility in Mg.},
doi = {10.1016/J.MATCHAR.2015.12.009},
journal = {Materials Characterization},
issn = {1044-5803},
number = ,
volume = 112,
place = {United States},
year = {2016},
month = {2}
}