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J H Sokolowski - One of the best experts on this subject based on the ideXlab platform.
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thermal and metallographic characteristics of the al 20 si high pressure die casting Alloy for monolithic cylinder blocks
Journal of Materials Processing Technology, 2008Co-Authors: H Yamagata, M Aniolek, H. Kurita, Włodzimierz Kasprzak, J H SokolowskiAbstract:Abstract Thermal analysis data were gathered to control the hypereutectic microstructure of the die-cast Al–20% Si cylinder block at a cooling rate of 1 °C/s. The liquidus temperature was approximately 691 ± 2.2 °C, the nucleation temperature of the Al–Si eutectic was approximately 567.1 ± 1.9 °C and the nucleation temperature of the Cu- and Mg-enriched eutectic was approximately 513.6 ± 1.4 °C. The fraction solid increases linearly from 0 to 21.6% when the temperature decreases from 691 to 567.1 °C. During the Al–Si eutectic growth the fraction solid rose to approximately 70% within a very narrow temperature range of 14 °C. The solidus temperature was recorded to be 479.9 ± 3.3 °C. The total solidification range for the investigated Alloy was approximately 211 °C. The rapid quenching experiments during the Alloy Melting cycle revealed the dissolution of the primary Si particles with the increasing temperature followed by complete Melting when the liquidus temperature were exceeded (i.e., 710.9 °C). It was found that a minimum superheat temperature of 80 °C was needed to achieve the adequate refinement of the primary Si particles as a combined effect of thermal and chemical modification. The results provided an extensive understanding of the thermal characteristics for the newly developed hypereutectic Al–20% Si Alloy and might be used to optimize the liquid metal handling on the foundry floor with respect to obtaining the required Alloy microstructural and service characteristics.
H Yamagata - One of the best experts on this subject based on the ideXlab platform.
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the effect of the melt temperature and the cooling rate on the microstructure of the al 20 si Alloy used for monolithic engine blocks
International Journal of Metalcasting, 2009Co-Authors: Włodzimierz Kasprzak, H Yamagata, M. Sahoo, J. Sokolowski, H. KuritaAbstract:The Al-20%Si melt heated to 785°C (1445°F) and 850°C (1562°F) exhibited refinement of the primary Si while heating to 735°C (1355°F) produced coarse and heterogeneous primary Si crystals following the solidification process at approximately 1.3, 4.5, 15 and 35°C/s. The primary Si crystals were 40% finer for the samples heated to 850°C (1562°F) as compared with those heated to 735°C (1355°F). Higher cooling rates produced better primary Si refinement and minimized its variation caused by the melt temperature. The secondary dendrite arm spacing (SDAS) was not affected by the melt temperature and was a function of the cooling rate for the given experimental conditions. The SDAS changed from approximately 32 to 22μm for a 1.3 and 4.5°C/s cooling rate and was reduced to approximately 11μm for a 35°C/s cooling rate. Cooling curve analysis was used to analyze the sequence of the metallurgical transformations and fraction liquid development during Alloy Melting and solidification. The non-equilibrium thermal characteristics under cooling rate up to 15°C/s were analyzed as well. The experimental results were used to optimize the casting process and improve the service characteristics of the vacuum assisted high pressure die casting (HPDC) motorcycle engine blocks.
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thermal and metallographic characteristics of the al 20 si high pressure die casting Alloy for monolithic cylinder blocks
Journal of Materials Processing Technology, 2008Co-Authors: H Yamagata, M Aniolek, H. Kurita, Włodzimierz Kasprzak, J H SokolowskiAbstract:Abstract Thermal analysis data were gathered to control the hypereutectic microstructure of the die-cast Al–20% Si cylinder block at a cooling rate of 1 °C/s. The liquidus temperature was approximately 691 ± 2.2 °C, the nucleation temperature of the Al–Si eutectic was approximately 567.1 ± 1.9 °C and the nucleation temperature of the Cu- and Mg-enriched eutectic was approximately 513.6 ± 1.4 °C. The fraction solid increases linearly from 0 to 21.6% when the temperature decreases from 691 to 567.1 °C. During the Al–Si eutectic growth the fraction solid rose to approximately 70% within a very narrow temperature range of 14 °C. The solidus temperature was recorded to be 479.9 ± 3.3 °C. The total solidification range for the investigated Alloy was approximately 211 °C. The rapid quenching experiments during the Alloy Melting cycle revealed the dissolution of the primary Si particles with the increasing temperature followed by complete Melting when the liquidus temperature were exceeded (i.e., 710.9 °C). It was found that a minimum superheat temperature of 80 °C was needed to achieve the adequate refinement of the primary Si particles as a combined effect of thermal and chemical modification. The results provided an extensive understanding of the thermal characteristics for the newly developed hypereutectic Al–20% Si Alloy and might be used to optimize the liquid metal handling on the foundry floor with respect to obtaining the required Alloy microstructural and service characteristics.
Saleh A Alkahtani - One of the best experts on this subject based on the ideXlab platform.
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effect of rare earth metals on the microstructure of al si based Alloys
Materials, 2016Co-Authors: Saleh A Alkahtani, E M Elgallad, Mahmoud M Tash, A M Samuel, F H SamuelAbstract:The present study was performed on A356 Alloy [Al-7 wt %Si 0.0.35 wt %Mg]. To that La and Ce were added individually or combined up to 1.5 wt % each. The results show that these rare earth elements affect only the Alloy Melting temperature with no marked change in the temperature of Al-Si eutectic precipitation. Additionally, rare earth metals have no modification effect up to 1.5 wt %. In addition, La and Ce tend to react with Sr leading to modification degradation. In order to achieve noticeable modification of eutectic Si particles, the concentration of rare earth metals should exceed 1.5 wt %, which simultaneously results in the precipitation of a fairly large volume fraction of insoluble intermetallics. The precipitation of these complex intermetallics is expected to have a negative effect on the Alloy performance.
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Effects of La and Ce Addition on the Modification of Al-Si Based Alloys
Hindawi Limited, 2016Co-Authors: Emad M. Elgallad, Saleh A Alkahtani, Herbert W. Doty, Fawzy H. SamuelAbstract:This study focuses on the effects of the addition of rare earth metals (mainly lanthanum and cerium) on the eutectic Si characteristics in Al-Si based Alloys. Based on the solidification curves and microstructural examination of the corresponding Alloys, it was found that addition of La or Ce increases the Alloy Melting temperature and the Al-Si eutectic temperature, with an Al-Si recalescence of 2-3°C, and the appearance of post-α-Al peaks attributed to precipitation of rare earth intermetallics. Addition of La or Ce to Al-(7–13)% Si causes only partial modification of the eutectic Si particles. Lanthanum has a high affinity to react with Sr, which weakens the modification efficiency of the latter. Cerium, however, has a high affinity for Ti, forming a large amount of sludge. Due to the large difference in the length of the eutectic Si particles in the same sample, the normal use of standard deviation in this case is meaningless
F H Samuel - One of the best experts on this subject based on the ideXlab platform.
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effect of rare earth metals on the microstructure of al si based Alloys
Materials, 2016Co-Authors: Saleh A Alkahtani, E M Elgallad, Mahmoud M Tash, A M Samuel, F H SamuelAbstract:The present study was performed on A356 Alloy [Al-7 wt %Si 0.0.35 wt %Mg]. To that La and Ce were added individually or combined up to 1.5 wt % each. The results show that these rare earth elements affect only the Alloy Melting temperature with no marked change in the temperature of Al-Si eutectic precipitation. Additionally, rare earth metals have no modification effect up to 1.5 wt %. In addition, La and Ce tend to react with Sr leading to modification degradation. In order to achieve noticeable modification of eutectic Si particles, the concentration of rare earth metals should exceed 1.5 wt %, which simultaneously results in the precipitation of a fairly large volume fraction of insoluble intermetallics. The precipitation of these complex intermetallics is expected to have a negative effect on the Alloy performance.
H. Kurita - One of the best experts on this subject based on the ideXlab platform.
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the effect of the melt temperature and the cooling rate on the microstructure of the al 20 si Alloy used for monolithic engine blocks
International Journal of Metalcasting, 2009Co-Authors: Włodzimierz Kasprzak, H Yamagata, M. Sahoo, J. Sokolowski, H. KuritaAbstract:The Al-20%Si melt heated to 785°C (1445°F) and 850°C (1562°F) exhibited refinement of the primary Si while heating to 735°C (1355°F) produced coarse and heterogeneous primary Si crystals following the solidification process at approximately 1.3, 4.5, 15 and 35°C/s. The primary Si crystals were 40% finer for the samples heated to 850°C (1562°F) as compared with those heated to 735°C (1355°F). Higher cooling rates produced better primary Si refinement and minimized its variation caused by the melt temperature. The secondary dendrite arm spacing (SDAS) was not affected by the melt temperature and was a function of the cooling rate for the given experimental conditions. The SDAS changed from approximately 32 to 22μm for a 1.3 and 4.5°C/s cooling rate and was reduced to approximately 11μm for a 35°C/s cooling rate. Cooling curve analysis was used to analyze the sequence of the metallurgical transformations and fraction liquid development during Alloy Melting and solidification. The non-equilibrium thermal characteristics under cooling rate up to 15°C/s were analyzed as well. The experimental results were used to optimize the casting process and improve the service characteristics of the vacuum assisted high pressure die casting (HPDC) motorcycle engine blocks.
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thermal and metallographic characteristics of the al 20 si high pressure die casting Alloy for monolithic cylinder blocks
Journal of Materials Processing Technology, 2008Co-Authors: H Yamagata, M Aniolek, H. Kurita, Włodzimierz Kasprzak, J H SokolowskiAbstract:Abstract Thermal analysis data were gathered to control the hypereutectic microstructure of the die-cast Al–20% Si cylinder block at a cooling rate of 1 °C/s. The liquidus temperature was approximately 691 ± 2.2 °C, the nucleation temperature of the Al–Si eutectic was approximately 567.1 ± 1.9 °C and the nucleation temperature of the Cu- and Mg-enriched eutectic was approximately 513.6 ± 1.4 °C. The fraction solid increases linearly from 0 to 21.6% when the temperature decreases from 691 to 567.1 °C. During the Al–Si eutectic growth the fraction solid rose to approximately 70% within a very narrow temperature range of 14 °C. The solidus temperature was recorded to be 479.9 ± 3.3 °C. The total solidification range for the investigated Alloy was approximately 211 °C. The rapid quenching experiments during the Alloy Melting cycle revealed the dissolution of the primary Si particles with the increasing temperature followed by complete Melting when the liquidus temperature were exceeded (i.e., 710.9 °C). It was found that a minimum superheat temperature of 80 °C was needed to achieve the adequate refinement of the primary Si particles as a combined effect of thermal and chemical modification. The results provided an extensive understanding of the thermal characteristics for the newly developed hypereutectic Al–20% Si Alloy and might be used to optimize the liquid metal handling on the foundry floor with respect to obtaining the required Alloy microstructural and service characteristics.