... By GASPAR GONZALEZ-DONCEL Centro Nacional de Investigaciones Metalurgicas, Avenida de Gregori... more ... By GASPAR GONZALEZ-DONCEL Centro Nacional de Investigaciones Metalurgicas, Avenida de Gregorio del Amo 8, 28040 Madrid, Spain ... Typical values for n in pure A1 for dislocation creep are about four to five with Q between 82 and 142 kJ mol-I (Frost and Ashby 1982). ...
En este trabajo se intenta relacionar el comportamiento mecanico de distintas aleaciones de alumi... more En este trabajo se intenta relacionar el comportamiento mecanico de distintas aleaciones de aluminio con sus caracteristicas microestructurales. Consta de tres partes y en cada una de ellas se estudia una aleacion especifica. En la primera se estudia una aleacion comercial de Al-4% Cu. El trabajo se centra en el efecto de los precipitados sobre los cambios de orientacion y fractura de probetas monocristalinas. En la segunda parte se estudia el comportamiento superplastico de la aleacion comercial 7475. Se propone un unico modelo de deslizamiento de fronteras de grano que explica la fluencia del material en un amplio intervalo de temperaturas. Por ultimo, se estudia la evolucion de la textura de la aleacion Al - 5% Ca - 5% Zn de pequeno tamano de grano durante la deformacion por traccion en distintas condiciones de ensayo.
Metallurgical and Materials Transactions, Jul 1, 1996
ABSTRACT The present work is part of an investigation into the use of rapid solidification and po... more ABSTRACT The present work is part of an investigation into the use of rapid solidification and powder metallurgy techniques to obtain iron-boron alloys with good mechanical properties. Two Fe-B binary alloys and two ultrahigh boron tool steels were gas atomized and consolidated by hot isostatic pressing (HIP) at temperatures ranging from 700 °C to 1100 °C to have a fine microstructure. Optimum properties were achieved for the binary alloys at low consolidation temperatures, since the solidification mi-crostructure from the original powders is eliminated and, at the same time, fine microstructures and low porosity are obtained in the alloys. At high temperatures and low strain rates, three of the four alloys exhibited low stress exponents, but only the Fe-2.2 pct B alloy showed tensile elongations higher than 100 pct. At low temperatures, only the Fe-2.2 pct B alloy deformed plastically. This alloy showed values of tensile elongation and ultimate tensile strength that were strongly dependent on testing and consolidation temperatures.
Surface investigation: x-ray, synchrotron and neutron techniques, Jul 1, 2021
A method is proposed to calculate the microscopic residual stresses in extruded cylindrical sampl... more A method is proposed to calculate the microscopic residual stresses in extruded cylindrical samples of non-ageing aluminium alloy 5083 (Al–Mg), arising from quenching in fresh water from 530°C. We start from the premise that the alloy is single-phase and non-isotropic on a microscopic scale; it consists of many grains that exhibit different mechanical response depending on their crystallographic orientation and neighboring grains. Microscopic residual stresses depend on the applied heat treatment, microstructure and mechanical strength of the individual grains. The stresses were calculated from neutron diffraction data. Genetic programming algorithms were used to calculate microscopic residual stresses, considering that each diffraction peak describes the stress distribution of a group of grains having a certain orientation, size and environment. The algorithm assigns a stress value to each grain according to the distribution of the diffraction peaks and the microstructural parameters of these grains.
The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350... more The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350 C was investigated. The as-cast material was warm-rolled which upon deformation at elevated temperature underwent dynamic recrystallization resulting in a fine-grained microstructure. The strain-rate-sensitivity exponent reached a maximum value of about 0.7 with elongations-to-failure as high as 610%. The strain-rate-sensitivity exponents for the warm-rolled Mg-8.5 wt.% Li alloy were similar to those obtained for fine-grained Mg-9 wt.% Li laminates processed using a foil metallurgy route. Higher elongations-to-failure were obtained in the warm-rolled alloy compared to the foil metallurgy processed alloy.
The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350... more The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350 C was investigated. The as-cast material was warm-rolled which upon deformation at elevated temperature underwent dynamic recrystallization resulting in a fine-grained microstructure. The strain-rate-sensitivity exponent reached a maximum value of about 0.7 with elongations-to-failure as high as 610%. The strain-rate-sensitivity exponents for the warm-rolled Mg-8.5 wt.% Li alloy were similar to those obtained for fine-grained Mg-9 wt.% Li laminates processed using a foil metallurgy route. Higher elongations-to-failure were obtained in the warm-rolled alloy compared to the foil metallurgy processed alloy.
... By GASPAR GONZALEZ-DONCEL Centro Nacional de Investigaciones Metalurgicas, Avenida de Gregori... more ... By GASPAR GONZALEZ-DONCEL Centro Nacional de Investigaciones Metalurgicas, Avenida de Gregorio del Amo 8, 28040 Madrid, Spain ... Typical values for n in pure A1 for dislocation creep are about four to five with Q between 82 and 142 kJ mol-I (Frost and Ashby 1982). ...
En este trabajo se intenta relacionar el comportamiento mecanico de distintas aleaciones de alumi... more En este trabajo se intenta relacionar el comportamiento mecanico de distintas aleaciones de aluminio con sus caracteristicas microestructurales. Consta de tres partes y en cada una de ellas se estudia una aleacion especifica. En la primera se estudia una aleacion comercial de Al-4% Cu. El trabajo se centra en el efecto de los precipitados sobre los cambios de orientacion y fractura de probetas monocristalinas. En la segunda parte se estudia el comportamiento superplastico de la aleacion comercial 7475. Se propone un unico modelo de deslizamiento de fronteras de grano que explica la fluencia del material en un amplio intervalo de temperaturas. Por ultimo, se estudia la evolucion de la textura de la aleacion Al - 5% Ca - 5% Zn de pequeno tamano de grano durante la deformacion por traccion en distintas condiciones de ensayo.
Metallurgical and Materials Transactions, Jul 1, 1996
ABSTRACT The present work is part of an investigation into the use of rapid solidification and po... more ABSTRACT The present work is part of an investigation into the use of rapid solidification and powder metallurgy techniques to obtain iron-boron alloys with good mechanical properties. Two Fe-B binary alloys and two ultrahigh boron tool steels were gas atomized and consolidated by hot isostatic pressing (HIP) at temperatures ranging from 700 °C to 1100 °C to have a fine microstructure. Optimum properties were achieved for the binary alloys at low consolidation temperatures, since the solidification mi-crostructure from the original powders is eliminated and, at the same time, fine microstructures and low porosity are obtained in the alloys. At high temperatures and low strain rates, three of the four alloys exhibited low stress exponents, but only the Fe-2.2 pct B alloy showed tensile elongations higher than 100 pct. At low temperatures, only the Fe-2.2 pct B alloy deformed plastically. This alloy showed values of tensile elongation and ultimate tensile strength that were strongly dependent on testing and consolidation temperatures.
Surface investigation: x-ray, synchrotron and neutron techniques, Jul 1, 2021
A method is proposed to calculate the microscopic residual stresses in extruded cylindrical sampl... more A method is proposed to calculate the microscopic residual stresses in extruded cylindrical samples of non-ageing aluminium alloy 5083 (Al–Mg), arising from quenching in fresh water from 530°C. We start from the premise that the alloy is single-phase and non-isotropic on a microscopic scale; it consists of many grains that exhibit different mechanical response depending on their crystallographic orientation and neighboring grains. Microscopic residual stresses depend on the applied heat treatment, microstructure and mechanical strength of the individual grains. The stresses were calculated from neutron diffraction data. Genetic programming algorithms were used to calculate microscopic residual stresses, considering that each diffraction peak describes the stress distribution of a group of grains having a certain orientation, size and environment. The algorithm assigns a stress value to each grain according to the distribution of the diffraction peaks and the microstructural parameters of these grains.
The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350... more The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350 C was investigated. The as-cast material was warm-rolled which upon deformation at elevated temperature underwent dynamic recrystallization resulting in a fine-grained microstructure. The strain-rate-sensitivity exponent reached a maximum value of about 0.7 with elongations-to-failure as high as 610%. The strain-rate-sensitivity exponents for the warm-rolled Mg-8.5 wt.% Li alloy were similar to those obtained for fine-grained Mg-9 wt.% Li laminates processed using a foil metallurgy route. Higher elongations-to-failure were obtained in the warm-rolled alloy compared to the foil metallurgy processed alloy.
The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350... more The superplastic behavior of a two-phase Mg-8.5 wt.% Li alloy in the temperature range 175 to 350 C was investigated. The as-cast material was warm-rolled which upon deformation at elevated temperature underwent dynamic recrystallization resulting in a fine-grained microstructure. The strain-rate-sensitivity exponent reached a maximum value of about 0.7 with elongations-to-failure as high as 610%. The strain-rate-sensitivity exponents for the warm-rolled Mg-8.5 wt.% Li alloy were similar to those obtained for fine-grained Mg-9 wt.% Li laminates processed using a foil metallurgy route. Higher elongations-to-failure were obtained in the warm-rolled alloy compared to the foil metallurgy processed alloy.
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