The Experts below are selected from a list of 5016 Experts worldwide ranked by ideXlab platform
Hamid Khayyam - One of the best experts on this subject based on the ideXlab platform.
-
al tib2 micro nanocomposites particle capture investigations strengthening mechanisms and mathematical modelling of mechanical properties
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2017Co-Authors: Mohammad Karbalaei Akbari, Zhenyin Hai, Serge Zhuiykov, Kamyar Shirvanimoghaddam, Hamid KhayyamAbstract:The interactions between suspended ceramic particles in composite slurry and advancing Solidification Front take place during liquid state processing of particle reinforced metal matrix composites. The introduced Solidification models in this research propose the possibility of nanoparticle engulfment by Solidification Front during gravity casting of molten composite. Results indicate that the strengthening mechanisms are considerably affected by the degree of particle engulfment and the quality of particle distribution in solid matrix. Microstructural studies show that nanoparticles are either engulfed inside metal grains or pushed by Solidification Front into the aluminum-silicon interface. The comparison of mechanical properties with the changes of secondary dendrite arm spacing proposes the dominance of Orowan strengthening mechanism in the samples reinforced by 0.5 vol% nanoparticles. The highest tensile properties are achieved in the composites reinforced by 1.5 vol% TiB2 nanoparticles. Experimental results of mechanical tests are constructed to create a multi-input and multi-output model by using a Neural Networks-Levenberg Marquardt Algorithm (NN-LMA). It is reported that the NN- LMA model is highly accurate (the margin of error is less than 5%) to predict the mechanical properties of Al-TiB2 composites.
-
Al-TiB2 micro/nanocomposites: Particle capture investigations, strengthening mechanisms and mathematical modelling of mechanical properties
Materials Science and Engineering A, 2017Co-Authors: Mohammad Karbalaei Akbari, Zhenyin Hai, Serge Zhuiykov, Kamyar Shirvanimoghaddam, Hamid KhayyamAbstract:The interactions between suspended ceramic particles in composite slurry and advancing Solidification Front take place during liquid state processing of particle reinforced metal matrix composites. The introduced Solidification models in this research propose the possibility of nanoparticle engulfment by Solidification Front during gravity casting of molten composite. Results indicate that the strengthening mechanisms are considerably affected by the degree of particle engulfment and the quality of particle distribution in solid matrix. Microstructural studies show that nanoparticles are either engulfed inside metal grains or pushed by Solidification Front into the aluminum-silicon interface. The comparison of mechanical properties with the changes of secondary dendrite arm spacing proposes the dominance of Orowan strengthening mechanism in the samples reinforced by 0.5 vol% nanoparticles. The highest tensile properties are achieved in the composites reinforced by 1.5 vol% TiB2 nanoparticles. Experimental results of mechanical tests are constructed to create a multi-input and multi-output model by using a Neural Networks-Levenberg Marquardt Algorithm (NN-LMA). It is reported that the NN- LMA model is highly accurate (the margin of error is less than 5%) to predict the mechanical properties of Al-TiB2 composites.
H S Udaykumar - One of the best experts on this subject based on the ideXlab platform.
-
multiscale modeling of particle Solidification Front dynamics part ii pushing engulfment transition
International Journal of Heat and Mass Transfer, 2007Co-Authors: J W Garvin, Yi Yang, H S UdaykumarAbstract:Abstract The interaction between a particle and an advancing Solidification Front is studied using a multi-scale computational model developed in Part I. The flow and temperature fields are solved separately at two disparate scales, i.e. at the overall system scale (“outer region”) and in the thin melt layer (“inner region”) between the particle and the Front. The solutions from the inner and outer regions are coupled at a matching region. The coupled dynamics of the particle and phase boundary motion, including lubrication and disjoining pressure effects in the premelted film between the particle and the Front is captured in the simulations. Results show that particle pushing (as opposed to particle engulfment) can occur when the ratio of thermal conductivity of the particle to the melt, kp/kl
-
multiscale modeling of particle Solidification Front dynamics part i methodology
International Journal of Heat and Mass Transfer, 2007Co-Authors: J W Garvin, Yi Yang, H S UdaykumarAbstract:Abstract The interaction between an advancing Solidification Front and a micron-size particle is an inherently multiscale heat and mass transport problem. Transport at the micro-scale (i.e. the scale of the particle dimension) couples with intermolecular interactions and lubrication forces in a thin layer of melt between the particle and the Front to determine the overall dynamics of the interaction. A multiscale model is developed to simulate such Front–particle interactions. The solution to the lubrication equations in the melt layer is coupled to the solution of the Navier–Stokes equations for the overall particle–Front system. Techniques are developed for coupling the dynamics at the two disparate scales at a common “matching plane”. All interfaces are represented and tracked using the level-set approach. A sharp-interface technique is employed for solution of the governing equations in the resulting moving boundary problem. Validation of the coupling strategy and results for the particle–Front interaction phenomenon with the multiscale approach are presented.
-
effect of a premelted film on the dynamics of particle Solidification Front interactions
Journal of Crystal Growth, 2006Co-Authors: J W Garvin, H S UdaykumarAbstract:Abstract Numerical simulations are performed to study the interaction of a Solidification Front with an embedded particle. A sharp-interface method is used to track both the phase boundary and the particle. The Solidification Front dynamics is fully coupled with particle motion. The main objective of the paper is to distinguish the role played by the premelted layer between the Solidification Front and the particle in determining conditions for particle engulfment. Results are obtained by assuming a premelted layer exists in the gap between the particle and the Solidification Front and compared to those assuming no premelted layer. In the absence of a premelted layer, arbitrary cut-off values for particle-Front gap thickness need to be invoked in order to define the critical velocity for which the pushing–engulfment transition occurs. When a premelted layer is assumed to exist, the prediction of the critical velocity is determined solely from the dynamics of the coupled Front–particle interaction. In addition, model predictions for the critical velocity based on a steady-state heat transfer analysis are shown to differ from that when the full dynamics of the phase boundary are taken into account.
-
drag on a ceramic particle being pushed by a metallic Solidification Front
Journal of Crystal Growth, 2005Co-Authors: J W Garvin, H S UdaykumarAbstract:Abstract The drag force experienced by a ceramic particle being steadily pushed by a metallic Solidification Front is calculated using a sharp interface numerical technique. The effects of thermal conductivity ratio between the particle and the melt (less than one for the ceramic–metal system) are accounted for in obtaining the drag expression. The drag expression is cast in two forms, the first expresses the drag as a function of the thermal conductivity ratio between the particle and the melt and the second as a function of the radius of curvature of the solid–liquid interface.
-
drag on a particle being pushed by a Solidification Front and its dependence on thermal conductivities
Journal of Crystal Growth, 2004Co-Authors: J W Garvin, H S UdaykumarAbstract:A particle approached by an advancing Solidification Front may be set in motion under the influence of forces that act across the narrow gap between it and the advancing Solidification Front. This particle motion induces a drag that promotes engulfment of the particle in the advancing solidifying medium. This drag force experienced by a particle being steadily pushed by a Solidification Front is studied numerically. A sharp-interface method is used to track both the phase boundary and the particle. The method employed in this paper allows for inclusion of the effects of thermal property differences between the particle and the melt. The dependency of the drag on the thermal conductivity ratio of the particle to the melt, as well as on the thickness of the thin gap between the solidifying interface and the particle, is examined. The results of the present calculations are compared with those of previous analyses. It is shown that previously used expressions for the drag on a particle may not correctly account for the effects of thermal conductivity of the particle.
A Pocheau - One of the best experts on this subject based on the ideXlab platform.
-
interaction of multiple particles with a Solidification Front from compacted particle layer to particle trapping
Langmuir, 2017Co-Authors: Brice Saintmichel, Sylvain Deville, Marc Georgelin, A PocheauAbstract:The interaction of Solidification Fronts with objects such as particles, droplets, cells, or bubbles is a phenomenon with many natural and technological occurrences. For an object facing the Front, it may yield various fates, from trapping to rejection, with large implications regarding the Solidification pattern. However, whereas most situations involve multiple particles interacting with each other and the Front, attention has focused almost exclusively on the interaction of a single, isolated object with the Front. Here we address experimentally the interaction of multiple particles with a Solidification Front by performing Solidification experiments of a monodisperse particle suspension in a Hele–Shaw cell with precise control of growth conditions and real-time visualization. We evidence the growth of a particle layer ahead of the Front at a close-packing volume fraction, and we document its steady-state value at various Solidification velocities. We then extend single-particle models to the situation...
-
Interaction of Multiple Particles with a Solidification Front: From Compacted Particle Layer to Particle Trapping
Langmuir, 2017Co-Authors: Brice Saint-michel, Sylvain Deville, Marc Georgelin, A PocheauAbstract:The interaction of Solidification Fronts with objects such as particles, droplets, cells, or bubbles is a phenomenon with many natural and technological occurrences. For an object facing the Front, it may yield various fates, from trapping to rejection, with large implications regarding the Solidification pattern. However, whereas most situations involve multiple particles interacting with each other and the Front, attention has focused almost exclusively on the interaction of a single, isolated object with the Front. Here we address experimentally the interaction of multiple particles with a Solidification Front by performing Solidification experiments of a monodisperse particle suspension in a Hele-Shaw cell, with precise control of growth conditions and real-time visualization. We evidence the growth of a particle layer ahead of the Front at a close-packing volume fraction and we document its steady state value at various Solidification velocities. We then extend single particle models to the situation of multiple particles by taking into account the additional force induced on an entering particle by viscous friction in the compacted particle layer. By a force balance model, this provides an indirect measure of the repelling mean thermomolecular pressure over a particle entering the Front. The presence of multiple particles is found to increase it following a reduction of the thickness of the thin liquid film that separates particles and Front. We anticipate the findings reported here to provide a relevant basis to understand many complex Solidification situations in geophysics, engineering, biology, or food engineering, where multiple objects interact with the Front and control the resulting Solidification patterns.
Mohammad Karbalaei Akbari - One of the best experts on this subject based on the ideXlab platform.
-
al tib2 micro nanocomposites particle capture investigations strengthening mechanisms and mathematical modelling of mechanical properties
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2017Co-Authors: Mohammad Karbalaei Akbari, Zhenyin Hai, Serge Zhuiykov, Kamyar Shirvanimoghaddam, Hamid KhayyamAbstract:The interactions between suspended ceramic particles in composite slurry and advancing Solidification Front take place during liquid state processing of particle reinforced metal matrix composites. The introduced Solidification models in this research propose the possibility of nanoparticle engulfment by Solidification Front during gravity casting of molten composite. Results indicate that the strengthening mechanisms are considerably affected by the degree of particle engulfment and the quality of particle distribution in solid matrix. Microstructural studies show that nanoparticles are either engulfed inside metal grains or pushed by Solidification Front into the aluminum-silicon interface. The comparison of mechanical properties with the changes of secondary dendrite arm spacing proposes the dominance of Orowan strengthening mechanism in the samples reinforced by 0.5 vol% nanoparticles. The highest tensile properties are achieved in the composites reinforced by 1.5 vol% TiB2 nanoparticles. Experimental results of mechanical tests are constructed to create a multi-input and multi-output model by using a Neural Networks-Levenberg Marquardt Algorithm (NN-LMA). It is reported that the NN- LMA model is highly accurate (the margin of error is less than 5%) to predict the mechanical properties of Al-TiB2 composites.
-
Al-TiB2 micro/nanocomposites: Particle capture investigations, strengthening mechanisms and mathematical modelling of mechanical properties
Materials Science and Engineering A, 2017Co-Authors: Mohammad Karbalaei Akbari, Zhenyin Hai, Serge Zhuiykov, Kamyar Shirvanimoghaddam, Hamid KhayyamAbstract:The interactions between suspended ceramic particles in composite slurry and advancing Solidification Front take place during liquid state processing of particle reinforced metal matrix composites. The introduced Solidification models in this research propose the possibility of nanoparticle engulfment by Solidification Front during gravity casting of molten composite. Results indicate that the strengthening mechanisms are considerably affected by the degree of particle engulfment and the quality of particle distribution in solid matrix. Microstructural studies show that nanoparticles are either engulfed inside metal grains or pushed by Solidification Front into the aluminum-silicon interface. The comparison of mechanical properties with the changes of secondary dendrite arm spacing proposes the dominance of Orowan strengthening mechanism in the samples reinforced by 0.5 vol% nanoparticles. The highest tensile properties are achieved in the composites reinforced by 1.5 vol% TiB2 nanoparticles. Experimental results of mechanical tests are constructed to create a multi-input and multi-output model by using a Neural Networks-Levenberg Marquardt Algorithm (NN-LMA). It is reported that the NN- LMA model is highly accurate (the margin of error is less than 5%) to predict the mechanical properties of Al-TiB2 composites.
J W Garvin - One of the best experts on this subject based on the ideXlab platform.
-
multiscale modeling of particle Solidification Front dynamics part ii pushing engulfment transition
International Journal of Heat and Mass Transfer, 2007Co-Authors: J W Garvin, Yi Yang, H S UdaykumarAbstract:Abstract The interaction between a particle and an advancing Solidification Front is studied using a multi-scale computational model developed in Part I. The flow and temperature fields are solved separately at two disparate scales, i.e. at the overall system scale (“outer region”) and in the thin melt layer (“inner region”) between the particle and the Front. The solutions from the inner and outer regions are coupled at a matching region. The coupled dynamics of the particle and phase boundary motion, including lubrication and disjoining pressure effects in the premelted film between the particle and the Front is captured in the simulations. Results show that particle pushing (as opposed to particle engulfment) can occur when the ratio of thermal conductivity of the particle to the melt, kp/kl
-
multiscale modeling of particle Solidification Front dynamics part i methodology
International Journal of Heat and Mass Transfer, 2007Co-Authors: J W Garvin, Yi Yang, H S UdaykumarAbstract:Abstract The interaction between an advancing Solidification Front and a micron-size particle is an inherently multiscale heat and mass transport problem. Transport at the micro-scale (i.e. the scale of the particle dimension) couples with intermolecular interactions and lubrication forces in a thin layer of melt between the particle and the Front to determine the overall dynamics of the interaction. A multiscale model is developed to simulate such Front–particle interactions. The solution to the lubrication equations in the melt layer is coupled to the solution of the Navier–Stokes equations for the overall particle–Front system. Techniques are developed for coupling the dynamics at the two disparate scales at a common “matching plane”. All interfaces are represented and tracked using the level-set approach. A sharp-interface technique is employed for solution of the governing equations in the resulting moving boundary problem. Validation of the coupling strategy and results for the particle–Front interaction phenomenon with the multiscale approach are presented.
-
effect of a premelted film on the dynamics of particle Solidification Front interactions
Journal of Crystal Growth, 2006Co-Authors: J W Garvin, H S UdaykumarAbstract:Abstract Numerical simulations are performed to study the interaction of a Solidification Front with an embedded particle. A sharp-interface method is used to track both the phase boundary and the particle. The Solidification Front dynamics is fully coupled with particle motion. The main objective of the paper is to distinguish the role played by the premelted layer between the Solidification Front and the particle in determining conditions for particle engulfment. Results are obtained by assuming a premelted layer exists in the gap between the particle and the Solidification Front and compared to those assuming no premelted layer. In the absence of a premelted layer, arbitrary cut-off values for particle-Front gap thickness need to be invoked in order to define the critical velocity for which the pushing–engulfment transition occurs. When a premelted layer is assumed to exist, the prediction of the critical velocity is determined solely from the dynamics of the coupled Front–particle interaction. In addition, model predictions for the critical velocity based on a steady-state heat transfer analysis are shown to differ from that when the full dynamics of the phase boundary are taken into account.
-
drag on a ceramic particle being pushed by a metallic Solidification Front
Journal of Crystal Growth, 2005Co-Authors: J W Garvin, H S UdaykumarAbstract:Abstract The drag force experienced by a ceramic particle being steadily pushed by a metallic Solidification Front is calculated using a sharp interface numerical technique. The effects of thermal conductivity ratio between the particle and the melt (less than one for the ceramic–metal system) are accounted for in obtaining the drag expression. The drag expression is cast in two forms, the first expresses the drag as a function of the thermal conductivity ratio between the particle and the melt and the second as a function of the radius of curvature of the solid–liquid interface.
-
drag on a particle being pushed by a Solidification Front and its dependence on thermal conductivities
Journal of Crystal Growth, 2004Co-Authors: J W Garvin, H S UdaykumarAbstract:A particle approached by an advancing Solidification Front may be set in motion under the influence of forces that act across the narrow gap between it and the advancing Solidification Front. This particle motion induces a drag that promotes engulfment of the particle in the advancing solidifying medium. This drag force experienced by a particle being steadily pushed by a Solidification Front is studied numerically. A sharp-interface method is used to track both the phase boundary and the particle. The method employed in this paper allows for inclusion of the effects of thermal property differences between the particle and the melt. The dependency of the drag on the thermal conductivity ratio of the particle to the melt, as well as on the thickness of the thin gap between the solidifying interface and the particle, is examined. The results of the present calculations are compared with those of previous analyses. It is shown that previously used expressions for the drag on a particle may not correctly account for the effects of thermal conductivity of the particle.