Arjun Dey | Indian Institute of Engineering Science and Technology, Shibpur (original) (raw)
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Papers by Arjun Dey
Ceramics International, 2009
The microplasma sprayed (MPS) hydroxyapatite (HAP) coating on surgical grade SS316L, is an emergi... more The microplasma sprayed (MPS) hydroxyapatite (HAP) coating on surgical grade SS316L, is an emerging material for bio-ceramic based implant application involving higher reliability. For this purpose, a 200 mm thick MPS-HAP coating was developed on SS316L substrate and characterized by XRD, SEM and FE-SEM techniques. The local mechanical properties of the coating, e.g. nano-hardness and Young's modulus were evaluated by nanoindentation technique carried out with a Berkovich indenter at various depths in the range of about 170-3000 nm on a polished top surface. The characteristic values of nano-hardness (1.5-5 GPa) and Young's modulus ($60-100 GPa) obtained through the application of Weibull statistics to the experimentally measured data revealed a strong indentation size effect (ISE). Attempts were made to explain the genesis of ISE on the basis of some existing and some new concepts. #
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
In this contribution, the experimental results of the nanoindentation response of the newly devel... more In this contribution, the experimental results of the nanoindentation response of the newly developed hydroxyapatitemullite composites are presented and analyzed. Three different composite compositions ie HAp-10wt% mullite, HAp-20wt% mullite and HAp-30wt% ...
Journal of Thermal Spray Technology, 2009
Microplasma sprayed (MIPS) HAP coatings on SS316L substrates were characterized by x-ray diffract... more Microplasma sprayed (MIPS) HAP coatings on SS316L substrates were characterized by x-ray diffraction, Fourier transformed infrared spectroscopy, optical microscopy, scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), atomic force microscopy and image analysis. The coating showed a high degree of crystallinity ~92%, a high porosity level of 20 vol.% and a moderate bonding strength of about 13 MPa. The displacement controlled three-point bend tests and associated results of optical microscopy indicated that crack deflection, crack branching, and also local crack bridging occurred during crack propagation in the coating. The nano-hardness (H) and Young’s modulus (E) of the MIPS-HAP coatings as measured by nanoindentation technique were about 6 and 92 GPa, respectively. The fracture toughness (K ic) of the coating was ~0.6 MPa·m0.5. From the nano-scratch experiments, the critical normal load at which localized microcracking led to delamination was measured to be ~400 mN.
Journal of Materials Science, 2009
Here we report the microstructural dependence of nano-hardness (H) and elastic modulus (E) of mic... more Here we report the microstructural dependence of nano-hardness (H) and elastic modulus (E) of microplasma sprayed (MIPS) 230 μm thick highly porous, heterogeneous hydroxyapatite (HAP) coating on SS316L. The nano-hardness and Young’s modulus data were measured on polished plan section (PS) of the coating by the nanoindentation technique with a Berkovich indenter. The characteristic values of nano-hardness and Young’s modulus were calculated through the application of Weibull statistics. Both nano-hardness and the Young’s modulus data showed an apparent indentation size effect. In addition, there was an increasing trend of Weibull moduli values for both the nano-hardness and the Young’s modulus data of the MIPS-HAP coating as the indentation load was enhanced from 10 to 1,000 mN. An attempt was made in the present work, to provide a qualitative model that can explain such behavior.
Journal of Non-crystalline Solids, 2011
For a thin commercial soda-lime-silica glass cover slip a significant increase in nanohardness (e... more For a thin commercial soda-lime-silica glass cover slip a significant increase in nanohardness (e.g. up to 74%) occurred with variations in the loading rate (10-20,000 μN·s − 1 ) along with presence of serrations in loaddepth plots and deformation band formation inside the nanoindentation cavity. These results are explained in terms of shear stress acting at positions of structural weakness close to the tip of the nanoindenter and the time scale of interaction between the nanoindenter and the local microstructure of the glass.
Journal of Materials Science, 2010
Symmetric shock experiments were conducted on a 10 μm grain size coarse alumina ceramic with a ga... more Symmetric shock experiments were conducted on a 10 μm grain size coarse alumina ceramic with a gas gun to identify its Hugoniot elastic limit (HEL). To understand the damage initiation and their subsequent growth mechanisms in coarse grain alumina subjected to shock impact at levels much above the HEL, additional asymmetric shock recovery experiments with the same gas gun were then deliberately conducted on the same alumina at shock pressure levels more than three times as high as the HEL and the fragments collected by a dedicated catcher system. Detailed characterization of the shock recovered alumina fragments by X-ray diffraction, nanoindentation, scanning electron microscopy, field emission scanning electron microscopy and transmission electron microscopy were utilized to understand the nature and process of failure initiation, incubational growth, coalescence and propagation leading to fragmentation. Based on these data a new qualitative damage model was developed to explain the deformation mechanism.
International Journal of Applied Ceramic Technology, 2010
We report the fracture toughness (KIc) measured by nanoindentation technique at five different lo... more We report the fracture toughness (KIc) measured by nanoindentation technique at five different loads in the range of 100–1000 mN on the cross section of a highly porous microplasma-sprayed hydroxyapatite (MIPS-HAP) coating. The unique advantage of this technique was that it could evaluate KIc at a scale comparable with that of the local microstructure of the coating. In spite of high porosity (∼11 vol%), the coating showed a toughness (∼0.6 MPa m0.5) comparable to typical literature data (∼0.5 MPa m0.5) on dense HAP coating. Scanning electron microscopy of nanoindents suggested some plausible reasons for achieving a relatively higher toughness in the coating.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010
In the current study, the experimental results on the nanoindentation response of both as prepare... more In the current study, the experimental results on the nanoindentation response of both as prepared and shock recovered alumina of 10 m grain size and identical processing history are presented and analyzed. The shock recovery experiments were deliberately conducted with gas gun arrangements at shock pressures much above the Hugoniot Elastic Limit (HEL) of alumina. The nanoindentation experiments were conducted at 10-1000 mN load with a Berkovich indenter. The nanohardness and Young's modulus value of shock recovered alumina were always lower than those of the as prepared alumina samples. Subsequently, the detailed characterizations of the shock recovered alumina samples by X-ray diffraction, scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were utilized to understand the reasons behind the drop in nanohardness and Young's modulus of shock recovered alumina samples.
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2010
To understand how hardness, the key design parameter for applications of brittle solids such as g... more To understand how hardness, the key design parameter for applications of brittle solids such as glass concerning contact deformation, is affected by loading rate variation, nanoindentation with a Berkovich tip was used to measure the nanohardness of a 330-μm-thick soda-lime-silica glass as a function of loading rate (1 to 1000 mN·s−1). The results showed for the very first time that, with variations in the loading rate, there was a 6 to 9 pct increase in the nanohardness of glass up to a threshold loading rate (TLR), whereafter it did not appreciably increase with further increase in loading rate. Further, the nanohardness data showed an indentation size effect (ISE) that obeyed the Meyer’s law. These observations were explained in terms of a strong shear stress component developed just beneath the nanoindenter and the related shear-induced deformation processes at local microstructural scale weak links. The significant or insignificant presence of shear-induced serrations in load depth plots and corresponding scanning electron microscopic evidence of a strong or mild presence of shear deformation bands in and around the nanoindentation cavity supported such a rationalization. Finally, a qualitative picture was developed for different deformation processes induced at various loading rates in glass.
Ceramics International
Bismuth ferrite (BiFeO 3 ) is a unique magnetoelectric multiferroic that exhibits the coexistence... more Bismuth ferrite (BiFeO 3 ) is a unique magnetoelectric multiferroic that exhibits the coexistence of ferroelectricity and antiferromagnetism at room temperature. This unique combination of properties has pumped a huge surge in current research on BiFeO 3 as a future material for very important technological applications such as magnetic detectors and as an active layer in magnetoelectric memories. For such applications involving miniaturized components and devices, it is essentially important to have an idea of the mechanical integrity of the system at the scale of the microstructure. In spite of the wealth of the literature, however, the attempt to evaluate the mechanical integrity of nano BiFeO 3 at a scale comparable with the local microstructural length scale was almost non-existent. Here we report, possibly for the first time the nanoindentation behaviour of a sol-gel process derived nano BiFeO 3 having particle size of 5-25 nm. The nanoindentation studies were conducted at 100-1000 mN loads on a green pellet annealed at a low temperature of only 300 8C to avoid particle coarsening. The results showed interesting dependence of nanohardness and Young's modulus on the nanoindentation load which could be explained in terms of elastic recovery and plastic deformation energy concepts. #
Books by Arjun Dey
Thesis links by Arjun Dey
Ceramics International, 2009
The microplasma sprayed (MPS) hydroxyapatite (HAP) coating on surgical grade SS316L, is an emergi... more The microplasma sprayed (MPS) hydroxyapatite (HAP) coating on surgical grade SS316L, is an emerging material for bio-ceramic based implant application involving higher reliability. For this purpose, a 200 mm thick MPS-HAP coating was developed on SS316L substrate and characterized by XRD, SEM and FE-SEM techniques. The local mechanical properties of the coating, e.g. nano-hardness and Young's modulus were evaluated by nanoindentation technique carried out with a Berkovich indenter at various depths in the range of about 170-3000 nm on a polished top surface. The characteristic values of nano-hardness (1.5-5 GPa) and Young's modulus ($60-100 GPa) obtained through the application of Weibull statistics to the experimentally measured data revealed a strong indentation size effect (ISE). Attempts were made to explain the genesis of ISE on the basis of some existing and some new concepts. #
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
In this contribution, the experimental results of the nanoindentation response of the newly devel... more In this contribution, the experimental results of the nanoindentation response of the newly developed hydroxyapatitemullite composites are presented and analyzed. Three different composite compositions ie HAp-10wt% mullite, HAp-20wt% mullite and HAp-30wt% ...
Journal of Thermal Spray Technology, 2009
Microplasma sprayed (MIPS) HAP coatings on SS316L substrates were characterized by x-ray diffract... more Microplasma sprayed (MIPS) HAP coatings on SS316L substrates were characterized by x-ray diffraction, Fourier transformed infrared spectroscopy, optical microscopy, scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), atomic force microscopy and image analysis. The coating showed a high degree of crystallinity ~92%, a high porosity level of 20 vol.% and a moderate bonding strength of about 13 MPa. The displacement controlled three-point bend tests and associated results of optical microscopy indicated that crack deflection, crack branching, and also local crack bridging occurred during crack propagation in the coating. The nano-hardness (H) and Young’s modulus (E) of the MIPS-HAP coatings as measured by nanoindentation technique were about 6 and 92 GPa, respectively. The fracture toughness (K ic) of the coating was ~0.6 MPa·m0.5. From the nano-scratch experiments, the critical normal load at which localized microcracking led to delamination was measured to be ~400 mN.
Journal of Materials Science, 2009
Here we report the microstructural dependence of nano-hardness (H) and elastic modulus (E) of mic... more Here we report the microstructural dependence of nano-hardness (H) and elastic modulus (E) of microplasma sprayed (MIPS) 230 μm thick highly porous, heterogeneous hydroxyapatite (HAP) coating on SS316L. The nano-hardness and Young’s modulus data were measured on polished plan section (PS) of the coating by the nanoindentation technique with a Berkovich indenter. The characteristic values of nano-hardness and Young’s modulus were calculated through the application of Weibull statistics. Both nano-hardness and the Young’s modulus data showed an apparent indentation size effect. In addition, there was an increasing trend of Weibull moduli values for both the nano-hardness and the Young’s modulus data of the MIPS-HAP coating as the indentation load was enhanced from 10 to 1,000 mN. An attempt was made in the present work, to provide a qualitative model that can explain such behavior.
Journal of Non-crystalline Solids, 2011
For a thin commercial soda-lime-silica glass cover slip a significant increase in nanohardness (e... more For a thin commercial soda-lime-silica glass cover slip a significant increase in nanohardness (e.g. up to 74%) occurred with variations in the loading rate (10-20,000 μN·s − 1 ) along with presence of serrations in loaddepth plots and deformation band formation inside the nanoindentation cavity. These results are explained in terms of shear stress acting at positions of structural weakness close to the tip of the nanoindenter and the time scale of interaction between the nanoindenter and the local microstructure of the glass.
Journal of Materials Science, 2010
Symmetric shock experiments were conducted on a 10 μm grain size coarse alumina ceramic with a ga... more Symmetric shock experiments were conducted on a 10 μm grain size coarse alumina ceramic with a gas gun to identify its Hugoniot elastic limit (HEL). To understand the damage initiation and their subsequent growth mechanisms in coarse grain alumina subjected to shock impact at levels much above the HEL, additional asymmetric shock recovery experiments with the same gas gun were then deliberately conducted on the same alumina at shock pressure levels more than three times as high as the HEL and the fragments collected by a dedicated catcher system. Detailed characterization of the shock recovered alumina fragments by X-ray diffraction, nanoindentation, scanning electron microscopy, field emission scanning electron microscopy and transmission electron microscopy were utilized to understand the nature and process of failure initiation, incubational growth, coalescence and propagation leading to fragmentation. Based on these data a new qualitative damage model was developed to explain the deformation mechanism.
International Journal of Applied Ceramic Technology, 2010
We report the fracture toughness (KIc) measured by nanoindentation technique at five different lo... more We report the fracture toughness (KIc) measured by nanoindentation technique at five different loads in the range of 100–1000 mN on the cross section of a highly porous microplasma-sprayed hydroxyapatite (MIPS-HAP) coating. The unique advantage of this technique was that it could evaluate KIc at a scale comparable with that of the local microstructure of the coating. In spite of high porosity (∼11 vol%), the coating showed a toughness (∼0.6 MPa m0.5) comparable to typical literature data (∼0.5 MPa m0.5) on dense HAP coating. Scanning electron microscopy of nanoindents suggested some plausible reasons for achieving a relatively higher toughness in the coating.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010
In the current study, the experimental results on the nanoindentation response of both as prepare... more In the current study, the experimental results on the nanoindentation response of both as prepared and shock recovered alumina of 10 m grain size and identical processing history are presented and analyzed. The shock recovery experiments were deliberately conducted with gas gun arrangements at shock pressures much above the Hugoniot Elastic Limit (HEL) of alumina. The nanoindentation experiments were conducted at 10-1000 mN load with a Berkovich indenter. The nanohardness and Young's modulus value of shock recovered alumina were always lower than those of the as prepared alumina samples. Subsequently, the detailed characterizations of the shock recovered alumina samples by X-ray diffraction, scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were utilized to understand the reasons behind the drop in nanohardness and Young's modulus of shock recovered alumina samples.
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2010
To understand how hardness, the key design parameter for applications of brittle solids such as g... more To understand how hardness, the key design parameter for applications of brittle solids such as glass concerning contact deformation, is affected by loading rate variation, nanoindentation with a Berkovich tip was used to measure the nanohardness of a 330-μm-thick soda-lime-silica glass as a function of loading rate (1 to 1000 mN·s−1). The results showed for the very first time that, with variations in the loading rate, there was a 6 to 9 pct increase in the nanohardness of glass up to a threshold loading rate (TLR), whereafter it did not appreciably increase with further increase in loading rate. Further, the nanohardness data showed an indentation size effect (ISE) that obeyed the Meyer’s law. These observations were explained in terms of a strong shear stress component developed just beneath the nanoindenter and the related shear-induced deformation processes at local microstructural scale weak links. The significant or insignificant presence of shear-induced serrations in load depth plots and corresponding scanning electron microscopic evidence of a strong or mild presence of shear deformation bands in and around the nanoindentation cavity supported such a rationalization. Finally, a qualitative picture was developed for different deformation processes induced at various loading rates in glass.
Ceramics International
Bismuth ferrite (BiFeO 3 ) is a unique magnetoelectric multiferroic that exhibits the coexistence... more Bismuth ferrite (BiFeO 3 ) is a unique magnetoelectric multiferroic that exhibits the coexistence of ferroelectricity and antiferromagnetism at room temperature. This unique combination of properties has pumped a huge surge in current research on BiFeO 3 as a future material for very important technological applications such as magnetic detectors and as an active layer in magnetoelectric memories. For such applications involving miniaturized components and devices, it is essentially important to have an idea of the mechanical integrity of the system at the scale of the microstructure. In spite of the wealth of the literature, however, the attempt to evaluate the mechanical integrity of nano BiFeO 3 at a scale comparable with the local microstructural length scale was almost non-existent. Here we report, possibly for the first time the nanoindentation behaviour of a sol-gel process derived nano BiFeO 3 having particle size of 5-25 nm. The nanoindentation studies were conducted at 100-1000 mN loads on a green pellet annealed at a low temperature of only 300 8C to avoid particle coarsening. The results showed interesting dependence of nanohardness and Young's modulus on the nanoindentation load which could be explained in terms of elastic recovery and plastic deformation energy concepts. #