The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Indranil Manna - One of the best experts on this subject based on the ideXlab platform.
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Studies on laser Surface Melting of Al-11% Si alloy
2020Co-Authors: Anirban Biswas, Indranil Manna, Barry L. Mordike, J. Dutta MajumdarAbstract:In the present investigation the effect of laser Surface Melting on wear and corrosion resistance of Al-11 wt.% Si alloy has been investigated. Laser Surface Melting has been carried out using a 2 kW continuous wave CO 2 laser at an applied power of 2.3 kW and scan speed ranging from 6 to 12 mm/min. Following the laser Surface Melting, a detailed investigation of the melted zone in terms of microstructure, composition and phases were undertaken. Mechanical properties of the melted zone were evaluated so far as the microhardness and wear resistance were concerned. The corro-sion behaviour of the as-received and the laser Surface melted Surface was evaluated in 1(M) H 2 SO 4 , 1(M) HNO 3 and 3.56 wt.% NaCl solutions. The microstructure of the melt zone consists of grain refinedAl andAl-Si eutec-tic colonies which results in an improved microhardness from 87 VHN as compared to 55 VHN of the as-received Al-Si alloy. The wear resistance of the melt Surface was improved significantly as compared to the as-received Al-Si alloy. A detailed corrosion study in various environments showed that corrosion resistance was marginally less in the 3.56 wt.% NaCl and 1 M H 2 SO 4 solutions, but was better in the 1 M HNO 3 solution.
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Studies on laser Surface Melting of tool steel—Part I: Surface characterization and it's electrochemical behavior
Surface & Coatings Technology, 2010Co-Authors: J. Dutta Majumdar, Ashish Kumar Nath, Indranil MannaAbstract:Abstract In the present study, the effect of laser Surface Melting of a tool steel (SAE 52100 steel) on the characteristics (microstructures, phases and residual stress) and the corrosion property of the treated Surface has been undertaken. Laser Surface Melting is carried out using a high power (2 kW) continuous wave CO 2 laser (with a beam diameter of 3 mm) with a linear scan speed of 1–2 m/min, using different proportions of argon (Ar) and nitrogen (N 2 ) as shrouding atmosphere. The gas flow rate was maintained constant at 6 l/min. Laser Surface Melting in argon (Ar) atmosphere significantly refined the microstructure (grain size) with the presence of lath martensite. Laser Surface Melting in 50%Ar + 50% N 2 and 100% N 2 atmosphere led to the formation of thin nitride (consisting of Fe 4 N and Fe 2 N and Cr 2 N) layer. Laser Surface Melting in 100% N 2 atmosphere developed a microstructure consisting of primary ferrite and eutectic mixtures of α-Fe and Fe 4 N, Fe 3 N, Fe 2 N and Cr 2 N. There is introduction of residual tensile micro-stress in laser Surface melted Surface. However, residual stress in the range of (− 800 to − 400 MPa) and (− 300 to + 100 MPa) were observed when Surface melted in 100% N 2 and 50%Ar–50% N 2 atmosphere. Improvement in general and pitting corrosion resistance in a 3.56 wt.% NaCl solution was noticed after laser Surface Melting.
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Studies on laser Surface Melting of tool steel — Part II: Mechanical properties of the Surface
Surface & Coatings Technology, 2010Co-Authors: J. Dutta Majumdar, Ashish Kumar Nath, Indranil MannaAbstract:In the present study, the effect of laser Surface Melting using different proportions of argon and nitrogen as shrouding atmosphere on microhardness and wear resistance properties of a low alloy high carbon tool steel (SAE 52100 steel) has been undertaken. Laser Surface Melting in argon (Ar) atmosphere significantly refined the microstructure (grain size) with the presence of carbides (both iron and chromium) and martensites and improved microhardness (350-500 VHN) as compared to as-received SAE 52100 steel (280 VHN). Laser Surface Melting in 100% N 2 atmosphere led to formation of thin nitride (consisting of Fe 4 N and Fe 2 N and Cr 2 N) layer with improved microhardness to as high as 1050 VHN. Wear studies showed a significant enhancement in wear resistance against hardened steel ball, a maximum improvement was achieved when lased using 100% N 2 . The mechanism of wear was studied in details.
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Studies on laser Surface Melting of tool steel-Part I: Surface characterization and it's electrochemical behavior
Surface and Coatings Technology, 2010Co-Authors: J. Dutta Majumdar, A K Nath, Indranil MannaAbstract:In the present study, the effect of laser Surface Melting of a tool steel (SAE 52100 steel) on the characteristics (microstructures, phases and residual stress) and the corrosion property of the treated Surface has been undertaken. Laser Surface Melting is carried out using a high power (2 kW) continuous wave CO2 laser (with a beam diameter of 3 mm) with a linear scan speed of 1-2 m/min, using different proportions of argon (Ar) and nitrogen (N2) as shrouding atmosphere. The gas flow rate was maintained constant at 6 l/min. Laser Surface Melting in argon (Ar) atmosphere significantly refined the microstructure (grain size) with the presence of lath martensite. Laser Surface Melting in 50%Ar + 50% N2 and 100% N2 atmosphere led to the formation of thin nitride (consisting of Fe4N and Fe2N and Cr2N) layer. Laser Surface Melting in 100% N2 atmosphere developed a microstructure consisting of primary ferrite and eutectic mixtures of α-Fe and Fe4N, Fe3N, Fe2N and Cr2N. There is introduction of residual tensile micro-stress in laser Surface melted Surface. However, residual stress in the range of (- 800 to - 400 MPa) and (- 300 to + 100 MPa) were observed when Surface melted in 100% N2 and 50%Ar-50% N2 atmosphere. Improvement in general and pitting corrosion resistance in a 3.56 wt.% NaCl solution was noticed after laser Surface Melting. © 2009 Elsevier B.V. All rights reserved.
J. Dutta Majumdar - One of the best experts on this subject based on the ideXlab platform.
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Studies on laser Surface Melting of Al-11% Si alloy
2020Co-Authors: Anirban Biswas, Indranil Manna, Barry L. Mordike, J. Dutta MajumdarAbstract:In the present investigation the effect of laser Surface Melting on wear and corrosion resistance of Al-11 wt.% Si alloy has been investigated. Laser Surface Melting has been carried out using a 2 kW continuous wave CO 2 laser at an applied power of 2.3 kW and scan speed ranging from 6 to 12 mm/min. Following the laser Surface Melting, a detailed investigation of the melted zone in terms of microstructure, composition and phases were undertaken. Mechanical properties of the melted zone were evaluated so far as the microhardness and wear resistance were concerned. The corro-sion behaviour of the as-received and the laser Surface melted Surface was evaluated in 1(M) H 2 SO 4 , 1(M) HNO 3 and 3.56 wt.% NaCl solutions. The microstructure of the melt zone consists of grain refinedAl andAl-Si eutec-tic colonies which results in an improved microhardness from 87 VHN as compared to 55 VHN of the as-received Al-Si alloy. The wear resistance of the melt Surface was improved significantly as compared to the as-received Al-Si alloy. A detailed corrosion study in various environments showed that corrosion resistance was marginally less in the 3.56 wt.% NaCl and 1 M H 2 SO 4 solutions, but was better in the 1 M HNO 3 solution.
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Studies on laser Surface Melting of tool steel—Part I: Surface characterization and it's electrochemical behavior
Surface & Coatings Technology, 2010Co-Authors: J. Dutta Majumdar, Ashish Kumar Nath, Indranil MannaAbstract:Abstract In the present study, the effect of laser Surface Melting of a tool steel (SAE 52100 steel) on the characteristics (microstructures, phases and residual stress) and the corrosion property of the treated Surface has been undertaken. Laser Surface Melting is carried out using a high power (2 kW) continuous wave CO 2 laser (with a beam diameter of 3 mm) with a linear scan speed of 1–2 m/min, using different proportions of argon (Ar) and nitrogen (N 2 ) as shrouding atmosphere. The gas flow rate was maintained constant at 6 l/min. Laser Surface Melting in argon (Ar) atmosphere significantly refined the microstructure (grain size) with the presence of lath martensite. Laser Surface Melting in 50%Ar + 50% N 2 and 100% N 2 atmosphere led to the formation of thin nitride (consisting of Fe 4 N and Fe 2 N and Cr 2 N) layer. Laser Surface Melting in 100% N 2 atmosphere developed a microstructure consisting of primary ferrite and eutectic mixtures of α-Fe and Fe 4 N, Fe 3 N, Fe 2 N and Cr 2 N. There is introduction of residual tensile micro-stress in laser Surface melted Surface. However, residual stress in the range of (− 800 to − 400 MPa) and (− 300 to + 100 MPa) were observed when Surface melted in 100% N 2 and 50%Ar–50% N 2 atmosphere. Improvement in general and pitting corrosion resistance in a 3.56 wt.% NaCl solution was noticed after laser Surface Melting.
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Studies on laser Surface Melting of tool steel — Part II: Mechanical properties of the Surface
Surface & Coatings Technology, 2010Co-Authors: J. Dutta Majumdar, Ashish Kumar Nath, Indranil MannaAbstract:In the present study, the effect of laser Surface Melting using different proportions of argon and nitrogen as shrouding atmosphere on microhardness and wear resistance properties of a low alloy high carbon tool steel (SAE 52100 steel) has been undertaken. Laser Surface Melting in argon (Ar) atmosphere significantly refined the microstructure (grain size) with the presence of carbides (both iron and chromium) and martensites and improved microhardness (350-500 VHN) as compared to as-received SAE 52100 steel (280 VHN). Laser Surface Melting in 100% N 2 atmosphere led to formation of thin nitride (consisting of Fe 4 N and Fe 2 N and Cr 2 N) layer with improved microhardness to as high as 1050 VHN. Wear studies showed a significant enhancement in wear resistance against hardened steel ball, a maximum improvement was achieved when lased using 100% N 2 . The mechanism of wear was studied in details.
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Studies on laser Surface Melting of tool steel-Part I: Surface characterization and it's electrochemical behavior
Surface and Coatings Technology, 2010Co-Authors: J. Dutta Majumdar, A K Nath, Indranil MannaAbstract:In the present study, the effect of laser Surface Melting of a tool steel (SAE 52100 steel) on the characteristics (microstructures, phases and residual stress) and the corrosion property of the treated Surface has been undertaken. Laser Surface Melting is carried out using a high power (2 kW) continuous wave CO2 laser (with a beam diameter of 3 mm) with a linear scan speed of 1-2 m/min, using different proportions of argon (Ar) and nitrogen (N2) as shrouding atmosphere. The gas flow rate was maintained constant at 6 l/min. Laser Surface Melting in argon (Ar) atmosphere significantly refined the microstructure (grain size) with the presence of lath martensite. Laser Surface Melting in 50%Ar + 50% N2 and 100% N2 atmosphere led to the formation of thin nitride (consisting of Fe4N and Fe2N and Cr2N) layer. Laser Surface Melting in 100% N2 atmosphere developed a microstructure consisting of primary ferrite and eutectic mixtures of α-Fe and Fe4N, Fe3N, Fe2N and Cr2N. There is introduction of residual tensile micro-stress in laser Surface melted Surface. However, residual stress in the range of (- 800 to - 400 MPa) and (- 300 to + 100 MPa) were observed when Surface melted in 100% N2 and 50%Ar-50% N2 atmosphere. Improvement in general and pitting corrosion resistance in a 3.56 wt.% NaCl solution was noticed after laser Surface Melting. © 2009 Elsevier B.V. All rights reserved.
Y R Shen - One of the best experts on this subject based on the ideXlab platform.
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Surface vibrational spectroscopic study of Surface Melting of ice
Physical Review Letters, 2001Co-Authors: Paulo B Miranda, Y R ShenAbstract:: Surface Melting on the (0001) face of hexagonal ice ( I(h)) was studied by sum-frequency vibrational spectroscopy in the OH stretch frequency range. The degree of orientational order of the dangling OH bonds at the Surface was measured as a function of temperature. Disordering sets in around 200 K and increases dramatically with temperature. The results show that the disordered (quasiliquid) layer on ice is structurally different from normal liquid water.
Joost W. M. Frenken - One of the best experts on this subject based on the ideXlab platform.
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Surface Melting: dry, slippery, wet and faceted Surfaces
Surface Science, 1994Co-Authors: Joost W. M. Frenken, H.m. Van PinxterenAbstract:Abstract We briefly review Surface Melting and related forms of high-temperature Surface disordering. Apart from the familiar low-index crystal faces also vicinal Surfaces will be considered. In addition to Surface orientations which undergo “complete” Surface Melting and crystal faces which are non-Melting, there are orientations which exhibit “incomplete” Melting, and others which prefer to facet under the influence of Surface Melting. The relation between the Surface behaviour and the high-temperature equilibrium crystal shape will be addressed.
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New views on Surface Melting obtained with STM and ion scattering
Surface Science, 1993Co-Authors: Joost W. M. Frenken, H.m. Van Pinxteren, Laurens KuipersAbstract:This paper gives a brief account of three new phenomena related to the disordering process known as Surface Melting. Using scanning tunneling microscopy we demonstrate that under the influence of the attractive tip-Surface interaction, a Melting Surface can jump to contact and form a connecting neck to the tip. We employ medium-energy ion scattering to show that not all Surfaces can be classified simply as either Melting or non-Melting. We find Surface orientations exhibiting incomplete Surface Melting and we identify ranges of Surface orientations that undergo Surface-Melting induced faceting.
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Observation of Surface-Melting-Induced Faceting
EPL, 1993Co-Authors: H.m. Van Pinxteren, Joost W. M. FrenkenAbstract:Medium-energy-ion scattering measurements on vicinal Surfaces in the [10] zone around Pb(111), at a temperature close to the bulk Melting point, demonstrate a new phenomenon, Surface-Melting-induced faceting. A range is identified of Surface orientations θd < θ < θm which are unstable at high temperatures. These vicinal Surfaces spontaneously facet into the dry orientation θd and the melted orientation θm.
J.p. Van Der Eerden - One of the best experts on this subject based on the ideXlab platform.
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From Thermoelasticity to Surface Melting
Science and Technology of Crystal Growth, 1995Co-Authors: T. H. M. Van Den Berg, J.p. Van Der EerdenAbstract:In this contribution, we present the fundamental background of a thermoelastic criterion for Surface Melting with applications in Monte Carlo and/or Molecular Dynamics studies of atomic slabs and interfaces. As an example, we show some simulation results for different faces of Lennard-Jones (Ar) and Buckminster fullerene (C60) crystals. It turns out that for some of these systems the Surface layer melts below the bulk Melting point.
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Surface roughening, Surface Melting and crystal quality
Faraday Discussions, 1993Co-Authors: J.p. Van Der EerdenAbstract:The modelling of crystal Surfaces, both in equilibrium and during growth, is now at a stage where the relation between Surface structure and crystal quality are accessible for future studies. The classical point of view is that the roughening transition marks the transition from step growth to rough growth with qualitative changes in the growth rate and the morphology. The Surface-Melting transition marks a change from solid-like to liquid-like Surface layers. This enhances the kinetics and will decrease the anisotropy of equilibrium Surface properties. It has been shown that Surface Melting may also lead to a linear growth law. Slightly speculative arguments are given to illustrate how Surface roughness and softness are related to morphological instability, impurity incorporation, mother-phase inclusions, dislocation formation and stacking faults.
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Relevance of Surface roughening and Surface Melting for crystal growth
Journal of Crystal Growth, 1993Co-Authors: J.p. Van Der EerdenAbstract:Abstract There are several new developments in the field of structural phase transitions in the interfacial region. In this paper, the point of view is taken that the roughening transition is of primary importance for the qualitative understanding of various phenomena related to crystal growth. Despite this, the understanding of Surface roughening alone is insufficient since in many experimental situations other types of Surface structure changes modify the characteristic roughening phenomena to such an extent that qualitatively new observations are reported. One of the interfering phenomena is Surface Melting, and therefore a good understanding of Surface Melting is shown to be relevant, not only for theoretical studies, but also for the correct interpretation of common effects during the growth of crystals.
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Fundamental criterion for Surface Melting
Journal of Crystal Growth, 1993Co-Authors: J.p. Van Der Eerden, T. H. M. Van Den Berg, J. Huinink, H.j.f. KnopsAbstract:Abstract Using the vanishing of the Surface shear modulus as a criterion for Surface Melting, we studied the (111) and (001) faces of Lennard-Jones crystals using Monte Carlo simulation methods. It turns out that on both faces the Surface layer melts below the bulk Melting point. Taking Lennard-Jones parameters relevant for argon, we find that the Surface shear modulus vanishes at 63± 1 K and 64±2 K for the (111) and the (001) Surface, whereas the bulk Melting point is estimated to be 72±1 K. Rough estimates for the Melting points of the second layer are 71±1 K and 70±2 K for (111) and (001) Surfaces, respectively.
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Surface roughening versus Surface Melting on Lennard-Jones crystal Surfaces
Journal of Crystal Growth, 1990Co-Authors: J.p. Van Der Eerden, A. Roos, J.m. Van Der VeerAbstract:Abstract In this paper the definitions of Surface roughening and Surface Melting are first critically reviewed. It is shown how Surface Melting can best be related to Surface elastic properties. To calculate the latter from simulations, explicit expressions for the local elasticity tensor are necessary, which are not readily available in the literature. The explicit form including non-local contributions, is presented here in a form suitable for numerical simulation. A scalar invariant Melting criterion is proposed, as well as an analogous expression for Surface Melting. Finally possible results for Lennard-Jones systems are previewed.
