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Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd. ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd. ST Kinetics | Gupta M.,National University of Singapore
Composites Part A: Applied Science and Manufacturing | Year: 2011

ZK60A nanocomposite containing CNT nanoparticle reinforcement was fabricated using solidification processing followed by hot extrusion. The ZK60A nanocomposite exhibited smaller grain size than monolithic ZK60A, significantly reduced presence of intermetallic phase, reasonable CNT nanoparticle distribution, non-dominant (0 0 0 2) texture in the longitudinal direction, and 17% lower hardness than monolithic ZK60A. Compared to monolithic ZK60A (in tension), the ZK60A nanocomposite exhibited higher 0.2% TYS, UTS, failure strain and work of fracture (WOF) (+10%, +10%, +127% and +156%, respectively). Also, compared to monolithic ZK60A (in compression), the ZK60A nanocomposite exhibited lower 0.2% CYS (-14%) and higher UCS, failure strain and WOF (+5%, +69% and +58%, respectively). The effect of CNT nanoparticle integration on the enhanced tensile and compressive response of ZK60A is investigated in this paper. © 2010 Elsevier Ltd. All rights reserved.


Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd. ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd. ST Kinetics | Gupta M.,National University of Singapore
Composites Part A: Applied Science and Manufacturing | Year: 2011

ZK60A Nanocomposite containing Si3N4 nanoparticles was fabricated using solidification processing followed by hot extrusion. The ZK60A nanocomposite exhibited smaller grain size than monolithic ZK60A, significantly reduced presence of intermetallic phase, reasonable Si 3N4 nanoparticle distribution, non-dominant (0 0 0 2) texture in the longitudinal direction, and 12% lower hardness than monolithic ZK60A. Compared to monolithic ZK60A (in tension), the ZK60A nanocomposite simultaneously exhibited higher 0.2% TYS, UTS, failure strain and work of fracture (WOF) (+21%, +17%, +85% and +119%, respectively). Also, compared to monolithic ZK60A (in compression), the ZK60A nanocomposite exhibited lower 0.2% CYS (-33%) and higher UCS, failure strain and WOF (+16%, +53% and +48%, respectively). The effect of adding Si3N4 nanoparticles on the enhanced tensile and compressive response of ZK60A is investigated in this paper. © 2011 Elsevier Ltd. All rights reserved.


Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd ST Kinetics | Gupta M.,National University of Singapore
Journal of Nanoparticle Research | Year: 2011

ZK60A nanocomposite containing Al2O3 nanoparticle reinforcement (50 nm average size) was fabricated using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size to the monolithic alloy, reasonable Al2O3 nanoparticle distribution, non-dominant (0 0 0 2) texture in the longitudinal direction, and 15% higher hardness than the monolithic alloy. Compared to the monolithic alloy (in tension), the nanocomposite exhibited lower yield strength (0.2%TYS) (-4%) and higher ultimate strength (UTS), failure strain, and work of fracture (WOF) (+13%, +170%, and +200%, respectively). Compared to the monolithic alloy (in compression), the nanocomposite exhibited lower yield strength (0.2%CYS) (-5%) and higher ultimate strength (UCS), failure strain, and WOF (+6%, +41%, and +43%, respectively). The effects of Al2O 3 nanoparticle addition on the enhancement of tensile and compressive properties of ZK60A are investigated in this article. © 2011 Springer Science+Business Media B.V.


Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd. ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd. ST Kinetics | Gupta M.,National University of Singapore
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2013

This study is aimed at understanding the function of two nitride nanoparticles regarding altering the mechanical properties of hybrid magnesium alloys in relation to nanoparticle-matrix reactivity. Nitride nanoparticles were selected for reinforcement purposes due to the affinity between magnesium and nitrogen (in parallel with the well-known magnesium-oxygen affinity). AZ91/ZK60A and AZ31/AZ91 hybrid magnesium alloys were reinforced with AlN and Si 3N4 nanoparticles (respectively) using solidification processing followed by hot extrusion. Each nitride nanocomposite exhibited higher tensile strength than the corresponding monolithic hybrid alloy. However, AZ91/ZK60A/AlN exhibited slightly lower tensile ductility than AZ91/ZK60A, while AZ31/AZ91/Si3N4 exhibited higher tensile ductility than AZ31/AZ91. The formation of high strain zones (HSZs) (from particle surfaces inclusive) during tensile deformation as a significant mechanism supporting ductility enhancement was addressed. AZ91/ZK60A/AlN exhibited lower and higher compressive strength and ductility (respectively) compared to AZ91/ZK60A, while AZ31/AZ91/Si3N4 exhibited higher and unchanged compressive strength and ductility (respectively) compared to AZ31/AZ91. Nanograin formation (recrystallization) during room temperature compressive deformation (as a toughening mechanism) in relation to nanoparticle-stimulated nucleation (NSN) ability was also discussed. The beneficial (as well as comparative) effects of the respective nitride nanoparticle on each hybrid alloy are studied in this article. © 2012 The Minerals, Metals & Materials Society and ASM International.


Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd ST Kinetics | Gupta M.,National University of Singapore
Journal of Alloys and Compounds | Year: 2011

AZ31/AZ91 hybrid alloy nanocomposite containing Al2O3 nanoparticle reinforcement was fabricated using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size to the monolithic hybrid alloy, reasonable Al2O3 nanoparticle distribution, non-dominant (0 0 0 2) texture in the longitudinal direction, and 25% higher hardness than the monolithic hybrid alloy. Compared to the monolithic hybrid alloy (in tension), the nanocomposite synergistically exhibited higher 0.2%TYS, UTS, failure strain and work of fracture (WOF) (+12%, +7%, +99% and +108%, respectively). Compared to the monolithic hybrid alloy (in compression), the nanocomposite exhibited higher 0.2%CYS and UCS, and lower failure strain and WOF (+5%, +3%, -7% and -7%, respectively). The beneficial effects of Al 2O3 nanoparticle addition on the enhancement of tensile and compressive properties of AZ31/AZ91 hybrid alloy are investigated in this paper. © 2011 Elsevier B.V. All rights reserved.


Paramsothy M.,National University of Singapore | Tan X.H.,Singapore Technologies Kinetics Ltd. ST Kinetics | Chan J.,Singapore Technologies Kinetics Ltd. ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd. ST Kinetics | Gupta M.,National University of Singapore
Journal of Alloys and Compounds | Year: 2012

This study is aimed at understanding the ductility enhancing function of nanoparticles in a concentrated magnesium alloy (AZ81) nanocomposite. Al 2O 3 nanoparticles were selected for reinforcement purposes due to the well known affinity between magnesium and oxygen. AZ81 magnesium alloy was reinforced with Al 2O 3 nanoparticles using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size and hardness to the monolithic alloy, reasonable nanoparticle distribution and non-dominant (0 0 0 2) texture in the longitudinal direction. Compared to the monolithic alloy in both tension and compression, the nanocomposite exhibited higher failure strain (+66% and +18%, respectively) without significant compromise in strength, and higher energy absorbed until fracture (EA) (+71% and +12%, respectively). The beneficial effects of Al 2O 3 nanoparticle addition on the tensile and compressive ductility enhancement of AZ81 alloy is discussed in this paper. © 2012 Elsevier B.V. All rights reserved.


Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd. ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd. ST Kinetics | Gupta M.,National University of Singapore
Journal of Nanomaterials | Year: 2011

ZK60A nanocomposite containing TiC nanoparticles was fabricated using solidification processing followed by hot extrusion. The ZK60A nanocomposite exhibited similar grain size to monolithic ZK60A and significantly reduced presence of intermetallic phase, reasonable TiC nanoparticle distribution, nondominant (0 0 0 2) texture in the longitudinal direction, and 16 lower hardness than monolithic ZK60A. Compared to monolithic ZK60A (in tension), the ZK60A nanocomposite simultaneously exhibited higher 0.2 TYS, UTS, failure strain, and work of fracture (WOF) (+13, +15, +76, and +106, resp.). Also, compared to monolithic ZK60A (in compression), the ZK60A nanocomposite exhibited lower 0.2 CYS (-17) and higher UCS, failure strain, and WOF (+11, +29, and +34, resp.). The beneficial effect of adding TiC nanoparticles on the enhanced tensile and compressive response of ZK60A is investigated in this paper. © 2011 Muralidharan Paramsothy et al.


Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd ST Kinetics | Gupta M.,National University of Singapore
Journal of Nanoparticle Research | Year: 2012

In metal matrix composites, particle-matrix interfacial reactions are generally undesirable as this leads to poor interface formation where the particle-matrix stress transfer characteristics are inferior. This is of particular concern regarding magnesium alloy nanocomposites for wide ranging weight critical structural applications. In this study, various magnesium alloy nanocomposites containing Al 2O 3, carbon nanotube, TiC, or Si 3N 4 nanoparticle reinforcement were fabricated using solidification processing followed by hot extrusion. Here and for the first time, Nanoscale Electro Negative Interface Density (NENID) quantifies the nanoparticle-alloy matrix interfacial area per unit volume in the magnesium alloy nanocomposite taking into consideration the electronegativity of the nanoparticle reinforcement. We suggest that (1) NENID affects selected mechanical properties in magnesium alloy nanocomposites and (2) there are two joint mechanisms at nanoscale that enable tensile strength and ductility of the alloy nanocomposites to be simultaneously enhanced. We show that NENID indicates the possibility of relatively increased nanoparticle-alloy matrix interfacial reactions occurring while taking into account thermodynamic considerations. © 2012 Springer Science+Business Media B.V.


Paramsothy M.,National University of Singapore | Tan X.H.,Singapore Technologies Kinetics Ltd. ST Kinetics | Chan J.,Singapore Technologies Kinetics Ltd. ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd. ST Kinetics | Gupta M.,National University of Singapore
Materials and Design | Year: 2013

This study is aimed at understanding the ductility enhancing function of carbon nanotube (CNT) nanoparticles in a concentrated magnesium alloy (AZ81) nanocomposite. CNT nanoparticles were selected for reinforcement purposes due to the well known lack of affinity between magnesium and carbon. The nanocomposite exhibited similar grain size and hardness to the monolithic alloy, reasonable nanoparticle distribution and non-dominant (0. 0. 0. 2) texture in the longitudinal direction. Compared to the monolithic alloy in tension, the nanocomposite exhibited higher failure strain (+73%) without significant compromise in strength, and higher energy absorbed until fracture (EA) (+79%). Compared to the monolithic alloy in compression, the nanocomposite exhibited slightly lower failure strain (-6%) with significant compromise in strength, and slightly lower EA (-7%). The beneficial effects of CNT nanoparticle addition on tensile ductility enhancement (with occasional drastic increase in strength) of AZ81 alloy is discussed in this paper. © 2012 Elsevier Ltd.


Paramsothy M.,National University of Singapore | Chan J.,Singapore Technologies Kinetics Ltd ST Kinetics | Kwok R.,Singapore Technologies Kinetics Ltd ST Kinetics | Gupta M.,National University of Singapore
Materials Science and Engineering A | Year: 2011

The main aim of this study was to simultaneously increase tensile strength and ductility of AZ31/AZ91 hybrid magnesium alloy with Si3N4 nanoparticles. AZ31/AZ91 hybrid alloy nanocomposite containing Si3N4 nanoparticle reinforcement was fabricated using solidification processing followed by hot extrusion. The nanocomposite exhibited similar grain size to the monolithic hybrid alloy, reasonable Si3N4 nanoparticle distribution, non-dominant (0002) texture in the longitudinal direction, and 13% higher hardness than the monolithic hybrid alloy. Compared to the monolithic hybrid alloy (in tension), the nanocomposite simultaneously exhibited higher yield strength, ultimate strength, failure strain and work of fracture (+12%, +5%, +64% and +71%, respectively). Compared to the monolithic hybrid alloy (in compression), the nanocomposite exhibited higher yield strength and ultimate strength, lower failure strain and higher work of fracture (+35%, +4%, -6% and +6%, respectively). The beneficial effects of Si3N4 nanoparticle addition on the enhancement of tensile and compressive properties of AZ31/AZ91 hybrid alloy are investigated in this paper. © 2011 Elsevier B.V.

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