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Chedtha Puncreobutr - One of the best experts on this subject based on the ideXlab platform.
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quantifying the effects of grain refiner addition on the solidification of fe rich Intermetallics in al si cu alloys using in situ synchrotron x ray tomography
TMS Annual Meeting & Exhibition, 2018Co-Authors: Surada Chuaypradit, Chedtha Puncreobutr, A B Phillion, Julie L Fife, P D LeeAbstract:The presence of Fe-rich Intermetallics, particularly β-Al5FeSi, in aluminium alloy cast components can often limit fatigue life. There is an on-going effort to control the formation of these detrimental phases through the additions of trace elements and grain refiners. However, the role of grain refinement on the formation of Intermetallics is still unclear and conflicting results exist. To gain better understanding, in situ synchrotron X-ray tomographic microscopy experiments were performed on a commercial Al–Si–Cu alloy with grain refiner addition. Three-dimensional microstructure evolution and intermetallic precipitation were quantified. The influence of the β-Intermetallics on the evolution of permeability during equiaxed dendritic solidification was also investigated numerically. The results illustrate that grain refinement affects α-Al grain structure as well as nucleation temperature of primary and intermetallic phases, but there is no evidence that it alters the precipitation sequence of Intermetallics or their morphology. The simulation results reveal that Intermetallics block interdendritic liquid flow and hence reduce permeability.
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in situ quantification of the nucleation and growth of fe rich Intermetallics during al alloy solidification
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, A B Phillion, Julie L Fife, P Rockett, A P Horsfield, P D LeeAbstract:Real-time in situ synchrotron X-ray tomographic microscopy was used to gain new insights into and quantify the nucleation mechanisms and growth kinetics of b-Al5FeSi Intermetallics during solidification of an aluminium Al–7.5Si–3.5Cu–0.6Fe (wt.%) alloy. Three new insights were obtained. First, the plate-like b-Intermetallics appeared to nucleate mainly on or near the primary aluminium dendrites and to a lesser extent off the oxide skin on the surface of the specimen. Second, for this alloy composition, b-intermetallic formation was largely complete before the formation of Al–Si eutectic. Third, the b-Intermetallics formed via fast lateral growth, wrapping around and in between the primary dendrite arms. Further, the nucleation and growth dynamics of b-Intermetallics were quantified as a function of undercooling in a functional form that could be easily used in microstructural simulations. The frequency of intermetallic interaction mechanisms, such as plate nucleation vs. impingement and branching, were also quantified. 2014 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/3.0/).
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influence of fe rich Intermetallics on solidification defects in al si cu alloys
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, Julie L Fife, P D Lee, K M Kareh, T Connolley, A B PhillionAbstract:Abstract To better understand the influence of Fe-rich Intermetallics on solidification defect formation, fast in situ synchrotron X-ray tomographic microscopy experiments were performed on a commercial A319 alloy (Al–7.5Si–3.5Cu, wt.%) with 0.2 and 0.6 wt.% Fe. Real-time observations during solidification and semi-solid deformation experiments reveal that β -Intermetallics contribute via several different mechanisms to porosity formation and hot tearing susceptibility. While β -Intermetallics were not observed to nucleate porosity directly, they do block interdendritic channels, thereby reducing the shrinkage feeding, and increasing pore tortuosity. Pores also grow preferentially along the surface of the β -Intermetallics, suggesting that the β -phase has a lower gas–solid interfacial energy than α-Al, thus assisting in increasing pore volume. During uniaxial tension experiments, the ductile failure of the semi-solid, intermetallic-poor, base alloy transitions to a brittle-like failure when a large amount of β -Intermetallics are present. In all post-failure microstructures, internal damage was preferentially orientated perpendicular to the loading direction, agreeing with prior experimental and numerical studies.
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coupling in situ synchrotron x ray tomographic microscopy and numerical simulation to quantify the influence of intermetallic formation on permeability in aluminium silicon copper alloys
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, A B Phillion, Julie L Fife, P D LeeAbstract:Abstract The influence of the β -Al 5 FeSi intermetallic phase on permeability evolution during solidification in an Al–Si–Cu alloy with a columnar dendritic microstructure has been numerically studied at solid fractions between 0.10 and 0.85. The fluid flow simulations were performed on a semisolid microstructure extracted directly from a single solidifying specimen, enabling the first study of permeability variation on an individual microstructure morphology that is evolving in solid fraction. The 3-D geometries were imaged at the TOMCAT beamline using 4-D (3-D + time) in situ synchrotron-based X-ray tomographic microscopy. The results illustrate the major effect of intermetallic particles on flow blockage and permeability. Intermetallics that grow normal to the flow direction were found to have a greater impact on the flow field in comparison to Intermetallics in the parallel flow direction. An analytical expression, based on the anisotropic Blake–Kozeny model, was developed with a particle blockage term that takes into account the effects of intermetallic particles on permeability. In the regime of primary-phase solidification, a good fit between the analytical expression and the simulation results is found.
P D Lee - One of the best experts on this subject based on the ideXlab platform.
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quantifying the effects of grain refiner addition on the solidification of fe rich Intermetallics in al si cu alloys using in situ synchrotron x ray tomography
TMS Annual Meeting & Exhibition, 2018Co-Authors: Surada Chuaypradit, Chedtha Puncreobutr, A B Phillion, Julie L Fife, P D LeeAbstract:The presence of Fe-rich Intermetallics, particularly β-Al5FeSi, in aluminium alloy cast components can often limit fatigue life. There is an on-going effort to control the formation of these detrimental phases through the additions of trace elements and grain refiners. However, the role of grain refinement on the formation of Intermetallics is still unclear and conflicting results exist. To gain better understanding, in situ synchrotron X-ray tomographic microscopy experiments were performed on a commercial Al–Si–Cu alloy with grain refiner addition. Three-dimensional microstructure evolution and intermetallic precipitation were quantified. The influence of the β-Intermetallics on the evolution of permeability during equiaxed dendritic solidification was also investigated numerically. The results illustrate that grain refinement affects α-Al grain structure as well as nucleation temperature of primary and intermetallic phases, but there is no evidence that it alters the precipitation sequence of Intermetallics or their morphology. The simulation results reveal that Intermetallics block interdendritic liquid flow and hence reduce permeability.
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in situ quantification of the nucleation and growth of fe rich Intermetallics during al alloy solidification
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, A B Phillion, Julie L Fife, P Rockett, A P Horsfield, P D LeeAbstract:Real-time in situ synchrotron X-ray tomographic microscopy was used to gain new insights into and quantify the nucleation mechanisms and growth kinetics of b-Al5FeSi Intermetallics during solidification of an aluminium Al–7.5Si–3.5Cu–0.6Fe (wt.%) alloy. Three new insights were obtained. First, the plate-like b-Intermetallics appeared to nucleate mainly on or near the primary aluminium dendrites and to a lesser extent off the oxide skin on the surface of the specimen. Second, for this alloy composition, b-intermetallic formation was largely complete before the formation of Al–Si eutectic. Third, the b-Intermetallics formed via fast lateral growth, wrapping around and in between the primary dendrite arms. Further, the nucleation and growth dynamics of b-Intermetallics were quantified as a function of undercooling in a functional form that could be easily used in microstructural simulations. The frequency of intermetallic interaction mechanisms, such as plate nucleation vs. impingement and branching, were also quantified. 2014 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/3.0/).
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influence of fe rich Intermetallics on solidification defects in al si cu alloys
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, Julie L Fife, P D Lee, K M Kareh, T Connolley, A B PhillionAbstract:Abstract To better understand the influence of Fe-rich Intermetallics on solidification defect formation, fast in situ synchrotron X-ray tomographic microscopy experiments were performed on a commercial A319 alloy (Al–7.5Si–3.5Cu, wt.%) with 0.2 and 0.6 wt.% Fe. Real-time observations during solidification and semi-solid deformation experiments reveal that β -Intermetallics contribute via several different mechanisms to porosity formation and hot tearing susceptibility. While β -Intermetallics were not observed to nucleate porosity directly, they do block interdendritic channels, thereby reducing the shrinkage feeding, and increasing pore tortuosity. Pores also grow preferentially along the surface of the β -Intermetallics, suggesting that the β -phase has a lower gas–solid interfacial energy than α-Al, thus assisting in increasing pore volume. During uniaxial tension experiments, the ductile failure of the semi-solid, intermetallic-poor, base alloy transitions to a brittle-like failure when a large amount of β -Intermetallics are present. In all post-failure microstructures, internal damage was preferentially orientated perpendicular to the loading direction, agreeing with prior experimental and numerical studies.
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coupling in situ synchrotron x ray tomographic microscopy and numerical simulation to quantify the influence of intermetallic formation on permeability in aluminium silicon copper alloys
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, A B Phillion, Julie L Fife, P D LeeAbstract:Abstract The influence of the β -Al 5 FeSi intermetallic phase on permeability evolution during solidification in an Al–Si–Cu alloy with a columnar dendritic microstructure has been numerically studied at solid fractions between 0.10 and 0.85. The fluid flow simulations were performed on a semisolid microstructure extracted directly from a single solidifying specimen, enabling the first study of permeability variation on an individual microstructure morphology that is evolving in solid fraction. The 3-D geometries were imaged at the TOMCAT beamline using 4-D (3-D + time) in situ synchrotron-based X-ray tomographic microscopy. The results illustrate the major effect of intermetallic particles on flow blockage and permeability. Intermetallics that grow normal to the flow direction were found to have a greater impact on the flow field in comparison to Intermetallics in the parallel flow direction. An analytical expression, based on the anisotropic Blake–Kozeny model, was developed with a particle blockage term that takes into account the effects of intermetallic particles on permeability. In the regime of primary-phase solidification, a good fit between the analytical expression and the simulation results is found.
A B Phillion - One of the best experts on this subject based on the ideXlab platform.
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quantifying the effects of grain refiner addition on the solidification of fe rich Intermetallics in al si cu alloys using in situ synchrotron x ray tomography
TMS Annual Meeting & Exhibition, 2018Co-Authors: Surada Chuaypradit, Chedtha Puncreobutr, A B Phillion, Julie L Fife, P D LeeAbstract:The presence of Fe-rich Intermetallics, particularly β-Al5FeSi, in aluminium alloy cast components can often limit fatigue life. There is an on-going effort to control the formation of these detrimental phases through the additions of trace elements and grain refiners. However, the role of grain refinement on the formation of Intermetallics is still unclear and conflicting results exist. To gain better understanding, in situ synchrotron X-ray tomographic microscopy experiments were performed on a commercial Al–Si–Cu alloy with grain refiner addition. Three-dimensional microstructure evolution and intermetallic precipitation were quantified. The influence of the β-Intermetallics on the evolution of permeability during equiaxed dendritic solidification was also investigated numerically. The results illustrate that grain refinement affects α-Al grain structure as well as nucleation temperature of primary and intermetallic phases, but there is no evidence that it alters the precipitation sequence of Intermetallics or their morphology. The simulation results reveal that Intermetallics block interdendritic liquid flow and hence reduce permeability.
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in situ quantification of the nucleation and growth of fe rich Intermetallics during al alloy solidification
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, A B Phillion, Julie L Fife, P Rockett, A P Horsfield, P D LeeAbstract:Real-time in situ synchrotron X-ray tomographic microscopy was used to gain new insights into and quantify the nucleation mechanisms and growth kinetics of b-Al5FeSi Intermetallics during solidification of an aluminium Al–7.5Si–3.5Cu–0.6Fe (wt.%) alloy. Three new insights were obtained. First, the plate-like b-Intermetallics appeared to nucleate mainly on or near the primary aluminium dendrites and to a lesser extent off the oxide skin on the surface of the specimen. Second, for this alloy composition, b-intermetallic formation was largely complete before the formation of Al–Si eutectic. Third, the b-Intermetallics formed via fast lateral growth, wrapping around and in between the primary dendrite arms. Further, the nucleation and growth dynamics of b-Intermetallics were quantified as a function of undercooling in a functional form that could be easily used in microstructural simulations. The frequency of intermetallic interaction mechanisms, such as plate nucleation vs. impingement and branching, were also quantified. 2014 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/3.0/).
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influence of fe rich Intermetallics on solidification defects in al si cu alloys
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, Julie L Fife, P D Lee, K M Kareh, T Connolley, A B PhillionAbstract:Abstract To better understand the influence of Fe-rich Intermetallics on solidification defect formation, fast in situ synchrotron X-ray tomographic microscopy experiments were performed on a commercial A319 alloy (Al–7.5Si–3.5Cu, wt.%) with 0.2 and 0.6 wt.% Fe. Real-time observations during solidification and semi-solid deformation experiments reveal that β -Intermetallics contribute via several different mechanisms to porosity formation and hot tearing susceptibility. While β -Intermetallics were not observed to nucleate porosity directly, they do block interdendritic channels, thereby reducing the shrinkage feeding, and increasing pore tortuosity. Pores also grow preferentially along the surface of the β -Intermetallics, suggesting that the β -phase has a lower gas–solid interfacial energy than α-Al, thus assisting in increasing pore volume. During uniaxial tension experiments, the ductile failure of the semi-solid, intermetallic-poor, base alloy transitions to a brittle-like failure when a large amount of β -Intermetallics are present. In all post-failure microstructures, internal damage was preferentially orientated perpendicular to the loading direction, agreeing with prior experimental and numerical studies.
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coupling in situ synchrotron x ray tomographic microscopy and numerical simulation to quantify the influence of intermetallic formation on permeability in aluminium silicon copper alloys
Acta Materialia, 2014Co-Authors: Chedtha Puncreobutr, A B Phillion, Julie L Fife, P D LeeAbstract:Abstract The influence of the β -Al 5 FeSi intermetallic phase on permeability evolution during solidification in an Al–Si–Cu alloy with a columnar dendritic microstructure has been numerically studied at solid fractions between 0.10 and 0.85. The fluid flow simulations were performed on a semisolid microstructure extracted directly from a single solidifying specimen, enabling the first study of permeability variation on an individual microstructure morphology that is evolving in solid fraction. The 3-D geometries were imaged at the TOMCAT beamline using 4-D (3-D + time) in situ synchrotron-based X-ray tomographic microscopy. The results illustrate the major effect of intermetallic particles on flow blockage and permeability. Intermetallics that grow normal to the flow direction were found to have a greater impact on the flow field in comparison to Intermetallics in the parallel flow direction. An analytical expression, based on the anisotropic Blake–Kozeny model, was developed with a particle blockage term that takes into account the effects of intermetallic particles on permeability. In the regime of primary-phase solidification, a good fit between the analytical expression and the simulation results is found.
Seungboo Jung - One of the best experts on this subject based on the ideXlab platform.
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effects of intermetallic compound on the electrical and mechanical properties of friction welded cu al bimetallic joints during annealing
Journal of Alloys and Compounds, 2005Co-Authors: Kueksaeng Bang, Seungboo JungAbstract:Abstract Al/Cu metal joints applied for the electrical connector was joined by the friction welding method to limit the formation of intermetallic compound under optimum friction welding condition. To guarantee the reliability of the Al/Cu joints in service requirement, the effects of the intermetallic compound layer on the electrical and mechanical properties have been investigated under various annealing conditions. Two kinds of intermetallic compounds layer were formed in the joints interface and identified by AlCu and Al 2 Cu. The growth kinetic of these Intermetallics during the annealing can be followed by volume diffusion process. The activation energy of Al 2 Cu, AlCu and total intermetallic compound (AlCu + Al 2 Cu) represented 107.5, 98.42 and 110.22 kJ/mol, respectively. A thicker intermetallic compound layers could seriously degrade the electrical resistivity and tensile strength. The electrical resistivity with 21 μm thickness of intermetallic compound was 45 μΩ cm and increased to be 85 μΩ cm with 107 μm of intermetallic compound. Tensile strength remarkably decreased from 85 MPa to near zero at the annealing condition of 773 K and 129.6 ks and fracture occurred through the intermetallic compound layers.
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effect of isothermal aging on intermetallic compound layer growth at the interface between sn 3 5ag 0 75cu solder and cu substrate
Journal of Materials Science, 2004Co-Authors: Jeongwon Yoon, Seungboo JungAbstract:Intermetallic compound (IMC) growth during solid-state isothermal aging at temperatures between 100 and 200°C up to 60 days for Sn-3.5Ag-0.75Cu solder on Cu substrate was investigated. A quantitative analysis of the IMC layer thickness as a function of aging time and temperature was performed. Diffusion couples showed a composite IMC layer comprised of Cu6Sn5 and Cu3Sn. After isothermal aging at temperature over 120°C, the solder/Cu interface exhibited a duplex structure of Cu6Sn5 and Cu3Sn Intermetallics. The growth of IMCs followed diffusion-controlled kinetics and the layer thickness reached 13 μm after 60 day of aging at 170°C. The apparent activation energies calculated for the growth of the total IMC (Cu6Sn5 + Cu3Sn), Cu6Sn5 and Cu3Sn intermetallic are 62.6, 49.1 and 80.1 kJ/mol, respectively.
P A S Reed - One of the best experts on this subject based on the ideXlab platform.
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micromechanisms of short fatigue crack growth in an al si piston alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: T O Mbuya, P A S ReedAbstract:Abstract The short fatigue crack growth behaviour of a model cast aluminium piston alloy has been investigated. This has been achieved using a combination of fatigue crack replication methods at various intervals during fatigue testing and post-mortem analysis of the crack profiles. Crack-microstructure interactions have been clearly delineated using a combination of optical microscopy and scanning electron microscopy. Results show that intermetallic particles and eutectic Al–Si regions play a significant role in determining the crack path and growth rate of short fatigue cracks. It is observed that the growth of short cracks is often retarded or even arrested at intermetallic particles and Al–Si eutectic regions. Crack deflection at Intermetallics and eutectic Si is also frequently observed. These results have been compared with the long crack growth behaviour of the alloy.
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micromechanisms of fatigue crack growth in cast aluminium piston alloys
International Journal of Fatigue, 2012Co-Authors: T O Mbuya, I Sinclair, A J Moffat, P A S ReedAbstract:Abstract The fatigue crack growth behaviour in as-cast and hot isostatically pressed (HIP) model cast aluminium piston alloys with hypoeutectic Si compositions of 6.9 wt% and 0.67 wt% has been investigated. The HIP alloys showed slightly improved fatigue crack growth resistance. Analysis of the crack path profiles and fracture surfaces showed that the crack tends to avoid Si and intermetallic particles at low Δ K levels up to a mid-Δ K of ∼7 MPa√m. However, some particles do fail ahead of the crack tip to facilitate crack advance due to the interconnected microstructure of these alloys. At higher levels of Δ K , the crack increasingly seeks out Si and intermetallic particles up to a Δ K of ∼9 MPa√m after which the crack preferentially propagates through intermetallic particles in the 0.67 wt%Si alloy or Si and Intermetallics in the 6.9 wt%Si alloys. It was also observed that crack interaction with Intermetallics caused crack deflections that led to roughness-induced crack closure and possibly oxide-induced crack closure at low to mid-Δ K . However, crack closure appears unimportant at high Δ K due to the large crack openings and evidenced by the fast crack growth rates observed.