... solidification parameters, such as the maximum temperature of primary α-Aluminium growth,temp... more ... solidification parameters, such as the maximum temperature of primary α-Aluminium growth,temperature and time difference between the maximum and minimum of the liquidus recalescence determined. ... Also, we have done tests in order to have a comparison with the Al ...
The aim of this work is to determine the Solid Fraction (SF) at the rigidity point (FRP) by apply... more The aim of this work is to determine the Solid Fraction (SF) at the rigidity point (FRP) by applying advanced thermal analysis techniques. The variation of the FRP value is important to explain the solidification behavior and the presence or absence of defects in aluminum alloys. As the final alloy composition plays a key role on obtained properties, the influence of major and minor alloying elements on FRP has been studied. A Taguchi design of experiments and a previously developed calculating method, based on the application of high rank derivatives has been employed to determinate first the rigidity point temperature (RPT) and after the corresponding FRP for AlSi10Mg alloys. A correlation factor of r2 of 0.81 was obtained for FRP calculation formula in function of the alloy composition.
The aim of this work is to study the calculation of the dendrite coherency point (DCP) by 12 thre... more The aim of this work is to study the calculation of the dendrite coherency point (DCP) by 12 three new methods and comparing them with the other methods of calculation and the influence of 13 the alloying elements over the DCP point in every of the studied methods. The DCP values of the 14 previous methods and sometimes difficult to calculate, due to the low variations in the analyzed 15 curves or the lack of loops, what makes difficult and automation with high accuracy of the DCP 16 determination. The proposed calculating methods are based on the calculations with the first 17 derivative of temperature respect time (dT/dt) curve versus time in the crossing with zero of the 18 second and third derivative after the maximum liquidus temperature, on the first derivative of 19 temperature respect time (dT/dt) curve versus temperature in the crossing with zero of the second 20 and third derivative after the maximum liquidus temperature and on the first derivative of the solid 21 fraction...
Refractory materials for aluminium industry are designed to be resistant to different degrees of ... more Refractory materials for aluminium industry are designed to be resistant to different degrees of thermal, mechanical and chemical wear. The refractory wall thickness reduction during service life increases the heat losses through walls decreasing the thermal efficiency of the furnace. Last developments are focused on obtaining refractories with better performance and improved insulation properties. On this regard, a simulation procedure has been developed to compare the thermal and chemical performance of different refractories during end use. This procedure includes measuring the internal and external wall temperatures of a testing furnace using thermography, and comparing the resistance to liquid aluminium determining the corundum and cracks appearance. Two refractories have been tested by this procedure for comparative purposes; a commercial alumina castable and an improved alumina castable with better insulation properties.
In this work, three novel complex concentrated aluminum alloys were developed. To investigate the... more In this work, three novel complex concentrated aluminum alloys were developed. To investigate the unexplored region of the multicomponent phase diagrams, thermo-physical parameters and the CALPHAD method were used to understand the phase formation of the Al80Mg5Sn5Zn5Ni5, Al80Mg5Sn5Zn5Mn5, and Al80Mg5Sn5Zn5Ti5 alloys. The ingots of the alloys were manufactured by a gravity permanent mold casting process, avoiding the use of expensive, dangerous, or scarce alloying elements. The microstructural evolution as a function of the variable element (Ni, Mn, or Ti) was studied by means of different microstructural characterization techniques. The hardness and compressive strength of the as-cast alloys at room temperature were studied and correlated with the previously characterized microstructures. All the alloys showed multiphase microstructures with major α-Al dendritic matrix reinforced with secondary phases. In terms of mechanical properties, the developed alloys exhibited a high compres...
The aim of this work is to give an overview of existing methods and to introduce three new method... more The aim of this work is to give an overview of existing methods and to introduce three new methods for the determination of the Dendrite Coherency Point (DCP) for AlSi10Mg alloys, as well as to compare the acquired values of DCP based on a thermal analysis and on the analysis of cooling curves working with only one thermocouple. Additionally, the impact of alloying and contaminant elements on the DCP will be also studied. The first two proposed methods employ the higher order derivatives of the cooling curves. The DCP was determined as the crossing point of the second and third derivative curves plotted versus time (method 1) or that of the temperature (method 2) with the zero line just after the maximum liquidus temperature. The third proposed method is based on the determination of the crossing point of the third solid fraction derivative curve with the zero line, corresponding to a minimum of the second derivative. A Taguchi design for the experiments was developed to study the D...
This work aims to calculate the rigidity point temperature of aluminum alloys by three new method... more This work aims to calculate the rigidity point temperature of aluminum alloys by three new methods and compare them with currently employed methods. The influence of major and minor alloying elements over the rigidity point temperature is also discussed. Until now it has been difficult to determine the exact temperature of the rigidity point, since small variations in the data obtained give variable results, making it difficult to automate the process with high accuracy. In this work we suggested three new mathematic methods based on the calculation of higher order derivatives of (dT/dt) with respect to time or temperature compared to those currently employed. A design of experiments based on the Taguchi method was employed to compare the effect of the major and minor alloying elements for the AlSi10Mg alloy, and to evaluate the accuracy of each developed method. Therefore, these systems will allow better automation of rigidity point temperature (RPT) determination, which is one of ...
International Journal of Materials Research, Oct 16, 2013
ABSTRACT Conventional high-pressure die casting aluminium components present certain limitations ... more ABSTRACT Conventional high-pressure die casting aluminium components present certain limitations in terms of mechanical properties attainable due to the intrinsic porosity of the castings as well as the presence of iron-based brittle intermetallic phases. The present work approaches the increase in ductility and tensile strength through the analysis of the effect of the alloying elements of Al-Si alloys used for high-pressure die casting. The combination of alloying elements providing the best results in terms of ductility and tensile strength were eventually selected to produce a batch of components that were thoroughly tested. The final alloy had a composition of Si 8.21, Fe 0.78, Cu 1.53, Mn 0.64, Mg 0.46, Ni 0.07, Zn 3.37, Pb 0.34, Sn 0.27, Ti 0.18 and Cr 0.04 wt.%. The selected alloy performance was compared to that of the commercial Al-Si9Cu3 and Silafont (R) 36 alloys.
This work aims to calculate the rigidity point temperature of aluminum alloys by three new method... more This work aims to calculate the rigidity point temperature of aluminum alloys by three new methods and compare them with currently employed methods. The influence of major and minor alloying elements over the rigidity point temperature is also discussed. Until now it has been difficult to determine the exact temperature of the rigidity point, since small variations in the data obtained give variable results, making it difficult to automate the process with high accuracy. In this work we suggested three new mathematic methods based on the calculation of higher order derivatives of (dT/dt) with respect to time or temperature compared to those currently employed. A design of experiments based on the Taguchi method was employed to compare the effect of the major and minor alloying elements for the AlSi10Mg alloy, and to evaluate the accuracy of each developed method. Therefore, these systems will allow better automation of rigidity point temperature (RPT) determination, which is one of ...
... solidification parameters, such as the maximum temperature of primary α-Aluminium growth,temp... more ... solidification parameters, such as the maximum temperature of primary α-Aluminium growth,temperature and time difference between the maximum and minimum of the liquidus recalescence determined. ... Also, we have done tests in order to have a comparison with the Al ...
The aim of this work is to determine the Solid Fraction (SF) at the rigidity point (FRP) by apply... more The aim of this work is to determine the Solid Fraction (SF) at the rigidity point (FRP) by applying advanced thermal analysis techniques. The variation of the FRP value is important to explain the solidification behavior and the presence or absence of defects in aluminum alloys. As the final alloy composition plays a key role on obtained properties, the influence of major and minor alloying elements on FRP has been studied. A Taguchi design of experiments and a previously developed calculating method, based on the application of high rank derivatives has been employed to determinate first the rigidity point temperature (RPT) and after the corresponding FRP for AlSi10Mg alloys. A correlation factor of r2 of 0.81 was obtained for FRP calculation formula in function of the alloy composition.
The aim of this work is to study the calculation of the dendrite coherency point (DCP) by 12 thre... more The aim of this work is to study the calculation of the dendrite coherency point (DCP) by 12 three new methods and comparing them with the other methods of calculation and the influence of 13 the alloying elements over the DCP point in every of the studied methods. The DCP values of the 14 previous methods and sometimes difficult to calculate, due to the low variations in the analyzed 15 curves or the lack of loops, what makes difficult and automation with high accuracy of the DCP 16 determination. The proposed calculating methods are based on the calculations with the first 17 derivative of temperature respect time (dT/dt) curve versus time in the crossing with zero of the 18 second and third derivative after the maximum liquidus temperature, on the first derivative of 19 temperature respect time (dT/dt) curve versus temperature in the crossing with zero of the second 20 and third derivative after the maximum liquidus temperature and on the first derivative of the solid 21 fraction...
Refractory materials for aluminium industry are designed to be resistant to different degrees of ... more Refractory materials for aluminium industry are designed to be resistant to different degrees of thermal, mechanical and chemical wear. The refractory wall thickness reduction during service life increases the heat losses through walls decreasing the thermal efficiency of the furnace. Last developments are focused on obtaining refractories with better performance and improved insulation properties. On this regard, a simulation procedure has been developed to compare the thermal and chemical performance of different refractories during end use. This procedure includes measuring the internal and external wall temperatures of a testing furnace using thermography, and comparing the resistance to liquid aluminium determining the corundum and cracks appearance. Two refractories have been tested by this procedure for comparative purposes; a commercial alumina castable and an improved alumina castable with better insulation properties.
In this work, three novel complex concentrated aluminum alloys were developed. To investigate the... more In this work, three novel complex concentrated aluminum alloys were developed. To investigate the unexplored region of the multicomponent phase diagrams, thermo-physical parameters and the CALPHAD method were used to understand the phase formation of the Al80Mg5Sn5Zn5Ni5, Al80Mg5Sn5Zn5Mn5, and Al80Mg5Sn5Zn5Ti5 alloys. The ingots of the alloys were manufactured by a gravity permanent mold casting process, avoiding the use of expensive, dangerous, or scarce alloying elements. The microstructural evolution as a function of the variable element (Ni, Mn, or Ti) was studied by means of different microstructural characterization techniques. The hardness and compressive strength of the as-cast alloys at room temperature were studied and correlated with the previously characterized microstructures. All the alloys showed multiphase microstructures with major α-Al dendritic matrix reinforced with secondary phases. In terms of mechanical properties, the developed alloys exhibited a high compres...
The aim of this work is to give an overview of existing methods and to introduce three new method... more The aim of this work is to give an overview of existing methods and to introduce three new methods for the determination of the Dendrite Coherency Point (DCP) for AlSi10Mg alloys, as well as to compare the acquired values of DCP based on a thermal analysis and on the analysis of cooling curves working with only one thermocouple. Additionally, the impact of alloying and contaminant elements on the DCP will be also studied. The first two proposed methods employ the higher order derivatives of the cooling curves. The DCP was determined as the crossing point of the second and third derivative curves plotted versus time (method 1) or that of the temperature (method 2) with the zero line just after the maximum liquidus temperature. The third proposed method is based on the determination of the crossing point of the third solid fraction derivative curve with the zero line, corresponding to a minimum of the second derivative. A Taguchi design for the experiments was developed to study the D...
This work aims to calculate the rigidity point temperature of aluminum alloys by three new method... more This work aims to calculate the rigidity point temperature of aluminum alloys by three new methods and compare them with currently employed methods. The influence of major and minor alloying elements over the rigidity point temperature is also discussed. Until now it has been difficult to determine the exact temperature of the rigidity point, since small variations in the data obtained give variable results, making it difficult to automate the process with high accuracy. In this work we suggested three new mathematic methods based on the calculation of higher order derivatives of (dT/dt) with respect to time or temperature compared to those currently employed. A design of experiments based on the Taguchi method was employed to compare the effect of the major and minor alloying elements for the AlSi10Mg alloy, and to evaluate the accuracy of each developed method. Therefore, these systems will allow better automation of rigidity point temperature (RPT) determination, which is one of ...
International Journal of Materials Research, Oct 16, 2013
ABSTRACT Conventional high-pressure die casting aluminium components present certain limitations ... more ABSTRACT Conventional high-pressure die casting aluminium components present certain limitations in terms of mechanical properties attainable due to the intrinsic porosity of the castings as well as the presence of iron-based brittle intermetallic phases. The present work approaches the increase in ductility and tensile strength through the analysis of the effect of the alloying elements of Al-Si alloys used for high-pressure die casting. The combination of alloying elements providing the best results in terms of ductility and tensile strength were eventually selected to produce a batch of components that were thoroughly tested. The final alloy had a composition of Si 8.21, Fe 0.78, Cu 1.53, Mn 0.64, Mg 0.46, Ni 0.07, Zn 3.37, Pb 0.34, Sn 0.27, Ti 0.18 and Cr 0.04 wt.%. The selected alloy performance was compared to that of the commercial Al-Si9Cu3 and Silafont (R) 36 alloys.
This work aims to calculate the rigidity point temperature of aluminum alloys by three new method... more This work aims to calculate the rigidity point temperature of aluminum alloys by three new methods and compare them with currently employed methods. The influence of major and minor alloying elements over the rigidity point temperature is also discussed. Until now it has been difficult to determine the exact temperature of the rigidity point, since small variations in the data obtained give variable results, making it difficult to automate the process with high accuracy. In this work we suggested three new mathematic methods based on the calculation of higher order derivatives of (dT/dt) with respect to time or temperature compared to those currently employed. A design of experiments based on the Taguchi method was employed to compare the effect of the major and minor alloying elements for the AlSi10Mg alloy, and to evaluate the accuracy of each developed method. Therefore, these systems will allow better automation of rigidity point temperature (RPT) determination, which is one of ...
Aluminium high pressure die casting (HPDC) is the most common process in order to produce alumini... more Aluminium high pressure die casting (HPDC) is the most common process in order to produce aluminium castings, due to the excellent balance of cost and properties for high series production volumes. The AlSi9Cu3 is the most common used aluminium alloy, representing approximately the 70% of the HPDC produced parts.
Nevertheless, conventional AlSiCu3 alloys present certain limitations in terms of mechanical properties attainable due to the intrinsic porosity of HPDC castings as well as the alloy composition. New process variants and alloys have been developed in recent years trying to improve these aspects.
AlSi9Cu3 standards have a wide range for alloying elements, that can vary for example in the AlSi9Cu3(Fe) EN-AC 46000 from 8-11% in the Silicon alloying element. For HPDC the standard properties are Elongation (E) < 1%, Yield strength (Y.E.) 140 MPa, Tensile Strength (T.S.) 240 Mpa and Hardness <80 HB. The present work approaches the development of new alloys similar to the AlSi9Cu3 alloys, but with tailored properties in function of the desired requirements. Specific ranges of compositions provide improvements in the elongation, yield strength, ultimate tensile strength and hardness and also combinations of them. As cast properties shows an alloy with E > 1%, Y.S. >200 MPa, T. S. >320 Mpa and Hardness >135 HB.
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Papers by Iban Vicario
Nevertheless, conventional AlSiCu3 alloys present certain
limitations in terms of mechanical properties attainable
due to the intrinsic porosity of HPDC castings as well as
the alloy composition. New process variants and alloys
have been developed in recent years trying to improve
these aspects.
AlSi9Cu3 standards have a wide range for alloying
elements, that can vary for example in the AlSi9Cu3(Fe)
EN-AC 46000 from 8-11% in the Silicon alloying
element. For HPDC the standard properties are
Elongation (E) < 1%, Yield strength (Y.E.) 140 MPa,
Tensile Strength (T.S.) 240 Mpa and Hardness <80 HB.
The present work approaches the development of new
alloys similar to the AlSi9Cu3 alloys, but with tailored
properties in function of the desired requirements.
Specific ranges of compositions provide improvements in
the elongation, yield strength, ultimate tensile strength
and hardness and also combinations of them. As cast
properties shows an alloy with E > 1%, Y.S. >200 MPa,
T. S. >320 Mpa and Hardness >135 HB.