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D Voss - One of the best experts on this subject based on the ideXlab platform.
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numerical study of convection induced peritectic macro segregation effect at the directional counter gravity solidification of ti 46al 8nb alloy
Intermetallics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace with power-down thermal profile operation. The laboratory refinement of cylindrical ingots growth technique was developed in course of terrestrial preparation experiments in the facility specially designed for a sounding Rocket Flight. Despite Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically-transformed microstructure was observed in solidified ingots, where Al content locally exceeds 47 at%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat–mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks-up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy obtained confirms the modeling findings.
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convection induced peritectic macro segregation proceeding at the directional solidification of ti 46al 8nb intermetallic alloy
Materials Chemistry and Physics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Authors extended the research on TiAl–Nb solidification/modeling reported in Kartavykh et al. (2010) [1] . Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at.%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace TEM 01-3M with power-down thermal profile operation. The laboratory refinement of this cylindrical ingot growth technique was developed in course of terrestrial preparation experiments in the furnace facility specially designed for a sounding Rocket Flight. Although Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically transformed microstructure was firstly observed in solidified ingots by SEM-BSE and EDX analyses, where Al content locally exceeds 47 at.%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat-mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy produced confirms the modeling findings. Valuable data are obtained for the optimization of cast processes of TiAl-intermetallics.
A V Kartavykh - One of the best experts on this subject based on the ideXlab platform.
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numerical study of convection induced peritectic macro segregation effect at the directional counter gravity solidification of ti 46al 8nb alloy
Intermetallics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace with power-down thermal profile operation. The laboratory refinement of cylindrical ingots growth technique was developed in course of terrestrial preparation experiments in the facility specially designed for a sounding Rocket Flight. Despite Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically-transformed microstructure was observed in solidified ingots, where Al content locally exceeds 47 at%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat–mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks-up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy obtained confirms the modeling findings.
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convection induced peritectic macro segregation proceeding at the directional solidification of ti 46al 8nb intermetallic alloy
Materials Chemistry and Physics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Authors extended the research on TiAl–Nb solidification/modeling reported in Kartavykh et al. (2010) [1] . Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at.%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace TEM 01-3M with power-down thermal profile operation. The laboratory refinement of this cylindrical ingot growth technique was developed in course of terrestrial preparation experiments in the furnace facility specially designed for a sounding Rocket Flight. Although Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically transformed microstructure was firstly observed in solidified ingots by SEM-BSE and EDX analyses, where Al content locally exceeds 47 at.%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat-mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy produced confirms the modeling findings. Valuable data are obtained for the optimization of cast processes of TiAl-intermetallics.
James D. Phillips - One of the best experts on this subject based on the ideXlab platform.
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a weak equivalence principle test on a suborbital Rocket
Classical and Quantum Gravity, 2010Co-Authors: Robert D Reasenberg, James D. PhillipsAbstract:We describe a Galilean test of the weak equivalence principle, to be conducted during the free fall portion of a sounding Rocket Flight. The test of a single pair of substances is aimed at a measurement uncertainty of ?(?) < 10?16 after averaging the results of eight separate drops. The weak equivalence principle measurement is made with a set of four laser gauges that are expected to achieve 0.1 pm Hz?1/2. The discovery of a violation (? ? 0) would have profound implications for physics, astrophysics and cosmology.
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a weak equivalence principle test on a suborbital Rocket
arXiv: General Relativity and Quantum Cosmology, 2010Co-Authors: Robert D Reasenberg, James D. PhillipsAbstract:We describe a Galilean test of the weak equivalence principle, to be conducted during the free fall portion of a sounding Rocket Flight. The test of a single pair of substances is aimed at a measurement uncertainty of sigma(eta) < 10^-16 after averaging the results of eight separate drops. The weak equivalence principle measurement is made with a set of four laser gauges that are expected to achieve 0.1 pm Hz^-1/2. The discovery of a violation (eta not equal to 0) would have profound implications for physics, astrophysics, and cosmology.
U Hecht - One of the best experts on this subject based on the ideXlab platform.
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numerical study of convection induced peritectic macro segregation effect at the directional counter gravity solidification of ti 46al 8nb alloy
Intermetallics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace with power-down thermal profile operation. The laboratory refinement of cylindrical ingots growth technique was developed in course of terrestrial preparation experiments in the facility specially designed for a sounding Rocket Flight. Despite Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically-transformed microstructure was observed in solidified ingots, where Al content locally exceeds 47 at%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat–mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks-up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy obtained confirms the modeling findings.
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convection induced peritectic macro segregation proceeding at the directional solidification of ti 46al 8nb intermetallic alloy
Materials Chemistry and Physics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Authors extended the research on TiAl–Nb solidification/modeling reported in Kartavykh et al. (2010) [1] . Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at.%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace TEM 01-3M with power-down thermal profile operation. The laboratory refinement of this cylindrical ingot growth technique was developed in course of terrestrial preparation experiments in the furnace facility specially designed for a sounding Rocket Flight. Although Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically transformed microstructure was firstly observed in solidified ingots by SEM-BSE and EDX analyses, where Al content locally exceeds 47 at.%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat-mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy produced confirms the modeling findings. Valuable data are obtained for the optimization of cast processes of TiAl-intermetallics.
S Rex - One of the best experts on this subject based on the ideXlab platform.
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numerical study of convection induced peritectic macro segregation effect at the directional counter gravity solidification of ti 46al 8nb alloy
Intermetallics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace with power-down thermal profile operation. The laboratory refinement of cylindrical ingots growth technique was developed in course of terrestrial preparation experiments in the facility specially designed for a sounding Rocket Flight. Despite Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically-transformed microstructure was observed in solidified ingots, where Al content locally exceeds 47 at%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat–mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks-up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy obtained confirms the modeling findings.
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convection induced peritectic macro segregation proceeding at the directional solidification of ti 46al 8nb intermetallic alloy
Materials Chemistry and Physics, 2011Co-Authors: A V Kartavykh, V Ginkin, S Ganina, S Rex, U Hecht, B Schmitz, D VossAbstract:Abstract Authors extended the research on TiAl–Nb solidification/modeling reported in Kartavykh et al. (2010) [1] . Unidirectional counter-gravity (upward) melt solidification of Ti–46Al–8Nb (at.%) intermetallic alloy was performed in the three-zone resistive tube electro-furnace TEM 01-3M with power-down thermal profile operation. The laboratory refinement of this cylindrical ingot growth technique was developed in course of terrestrial preparation experiments in the furnace facility specially designed for a sounding Rocket Flight. Although Ti–46Al–8Nb is nominally slightly pro-peritectic composition, an axial elongated channel-like area with peritectically transformed microstructure was firstly observed in solidified ingots by SEM-BSE and EDX analyses, where Al content locally exceeds 47 at.%. For revealing the reasons of this microstructural inhomogeneity formation, the numerical modeling was applied. The real-time-scale 2D temperature field mapping, macro-scale study of melt hydrodynamics, heat-mass transfer, segregation effects, mushy zone evolution and solidification dynamics of TiAl–Nb melt/solid system have been performed accordingly. It was found that appearance of peritectic axial “spindle” in the solid is induced by the joint action of two factors in the melt: (i) rejection of Al solute ahead of the concave growth interface (dendrite tips front); (ii) development of weak laminar thermo-gravitational convective flow that picks up, pulls upward and stratifies an Al-enriched stream along the axis of melt column. The driving force of convection is a radial thermal gradient that depends on the furnace operational thermal conditions. To prevent the segregation, it was shown numerically that single regular convective cell could be broken into several cells by the appropriate variation of power-down cooling rate. The resulting uniform as-solidified microstructure of alloy produced confirms the modeling findings. Valuable data are obtained for the optimization of cast processes of TiAl-intermetallics.
