Resolving the strength-ductility paradox through severe plastic deformation of a cast Al-7% Si alloy
Resolving the strength-ductility paradox through severe plastic deformation of a cast Al-7% Si alloy
Ultrafine-grained (UFG) materials produced by severe plastic deformation (SPD) may show both enhanced ductility and strength and hence resolve the so-called strength-ductility paradox. To gain mechanistic insights into such resolution, the effect of high-pressure torsion (HPT) on the microstructure and mechanical behavior was studied using a cast Al-7 wt. % Si alloy. As expected, the grain size decreased while the fraction of high-angle grain boundaries and microhardness increased due to HPT processing. However, tensile testing at room temperature revealed a simultaneous increase in strength and ductility compared to the as-cast sample. The samples showing simultaneous increase in strength and ductility also showed an increased contribution from grain boundary sliding (GBS), even at room temperature, which is attributed to the existence of a high fraction of high-angle and high-energy grain boundaries. It is proposed that the occurrence of moderate GBS, providing ductility, in very small size grains provides Hall-Petch strengthening and this suggests a potential combination for simultaneously achieving high strength and high ductility in SPD-processed UFG materials.
1043-1048
Kumar, Praveen
6061332b-68e8-46ec-92ce-8ec6025748af
Kawasaki, Megumi
944ba471-eb78-46db-bfb7-3f0296d9ef6d
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
January 2017
Kumar, Praveen
6061332b-68e8-46ec-92ce-8ec6025748af
Kawasaki, Megumi
944ba471-eb78-46db-bfb7-3f0296d9ef6d
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Kumar, Praveen, Kawasaki, Megumi and Langdon, Terence G.
(2017)
Resolving the strength-ductility paradox through severe plastic deformation of a cast Al-7% Si alloy.
Materials Science Forum, 879, .
(doi:10.4028/www.scientific.net/MSF.879.1043).
Abstract
Ultrafine-grained (UFG) materials produced by severe plastic deformation (SPD) may show both enhanced ductility and strength and hence resolve the so-called strength-ductility paradox. To gain mechanistic insights into such resolution, the effect of high-pressure torsion (HPT) on the microstructure and mechanical behavior was studied using a cast Al-7 wt. % Si alloy. As expected, the grain size decreased while the fraction of high-angle grain boundaries and microhardness increased due to HPT processing. However, tensile testing at room temperature revealed a simultaneous increase in strength and ductility compared to the as-cast sample. The samples showing simultaneous increase in strength and ductility also showed an increased contribution from grain boundary sliding (GBS), even at room temperature, which is attributed to the existence of a high fraction of high-angle and high-energy grain boundaries. It is proposed that the occurrence of moderate GBS, providing ductility, in very small size grains provides Hall-Petch strengthening and this suggests a potential combination for simultaneously achieving high strength and high ductility in SPD-processed UFG materials.
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Accepted/In Press date: 23 September 2016
e-pub ahead of print date: 15 November 2016
Published date: January 2017
Organisations:
Engineering Mats & Surface Engineerg Gp
Identifiers
Local EPrints ID: 402933
URI: http://eprints.soton.ac.uk/id/eprint/402933
ISSN: 1662-9752
PURE UUID: c1072e1b-eb61-43c4-9d6a-a75d38ab9cce
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Date deposited: 18 Nov 2016 15:20
Last modified: 16 Mar 2024 03:28
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Author:
Praveen Kumar
Author:
Megumi Kawasaki
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