R. Mahmudi - Academia.edu (original) (raw)

Papers by R. Mahmudi

Research paper thumbnail of Evolutions of mechanical properties of AISI 304L stainless steel under shear loading

Materials Science and Engineering: A, 2020

Research paper thumbnail of Mechanical response of a metastable austenitic stainless steel under different deformation modes

Materials Science and Technology, 2021

The deformation behaviour of AISI 304L stainless steel was examined under uniaxial tension and sh... more The deformation behaviour of AISI 304L stainless steel was examined under uniaxial tension and shear deformation modes in the temperature range of 0–500°C. A linear relationship between the tensile and shear yield stresses was observed over the whole temperature range, which was in a good agreement with the predictions of the von-Mises criterion. The relationship between the ultimate shear and tensile strength values, however, showed three distinct temperature-dependent regimes. In the temperature ranges corresponding to the transformation-induced plasticity effect and the dynamic strain aging phenomenon, a deviation from the expected behaviour was observed, which was related to the dependency of these phenomena on the loading mode.

Research paper thumbnail of Effect of texture and twinning on mechanical properties and corrosion behavior of an extruded biodegradable Mg–4Zn alloy

Journal of Magnesium and Alloys, 2019

Research paper thumbnail of Enhanced microstructural stability and mechanical properties of the Ag-containing Mg–Gd–Y alloys

Journal of Magnesium and Alloys, 2020

Research paper thumbnail of Hot deformation behavior of an extruded AZ31 alloy doped with rare-earth elements

Journal of Alloys and Compounds, 2021

Research paper thumbnail of Tailoring the texture of an extruded Mg sheet through constrained groove pressing for achieving low mechanical anisotropy and high yield strength

Research paper thumbnail of Microstructure characterization and high-temperature shear strength of the Mg–10Gd–3Y–1.2Zn–0.5Zr alloy in the as-cast and aged conditions

Journal of Alloys and Compounds, 2015

Research paper thumbnail of Enhanced superplasticity in an extruded high strength Mg–Gd–Y–Zr alloy with Ag addition

Journal of Alloys and Compounds, 2015

Research paper thumbnail of Enhanced creep properties of a cast Mg–5Sn alloy subjected to aging-treatment

Materials Science and Engineering: A, 2010

The microstructure and impression creep behavior of the Mg–5Sn alloy are studied in the as-cast a... more The microstructure and impression creep behavior of the Mg–5Sn alloy are studied in the as-cast and aged conditions. Impression creep tests were performed in the temperature range 423–498K and under punching stresses in the range 125–400MPa. Analysis of the data showed that for all loads and temperatures, the creep resistance of the aged alloys was much better than that of

Research paper thumbnail of Surface roughening during uniaxial and equi-biaxial stretching of 70-30 brass sheets

Journal of Materials Processing Technology, 1998

The surface roughening behaviour of 70-30 brass sheets was investigated under uniaxial and equi-b... more The surface roughening behaviour of 70-30 brass sheets was investigated under uniaxial and equi-biaxial stress states. Attention was focused on two main industrial conditions of the materials, these being representative of the materials that could be processed by the commercial batch-annealing process (slow heating, long time) or by a continuous annealing process (fast heating, short time). These two regimes produced

Research paper thumbnail of Hot deformation constitutive analysis and processing maps of extruded Mg–Gd binary alloys

Journal of Materials Research and Technology, 2020

Research paper thumbnail of Impression creep of Sn–40Pb–2·5Sb peritectic solder alloy

Materials Science and Technology, 2005

Research paper thumbnail of Effect of rare earth elements addition on the tribological behavior of AZ91D magnesium alloy at elevated temperatures

Wear, 2013

ABSTRACT a b s t r a c t The effect of 1, 2, and 3 wt% of lanthanum-base rare earth (RE) element ... more ABSTRACT a b s t r a c t The effect of 1, 2, and 3 wt% of lanthanum-base rare earth (RE) element additions on the wear behavior of AZ91 alloy was investigated under a normal load of 20 N at the wear temperatures of 25–250 1C. The wear tests were carried out using a pin-on-disk tribometer at a sliding speed of 0.4 ms À 1 for a sliding distance of 1000 m. The results showed that there was no change in the wear rate of the alloys at the wear temperature of 25 1C. By increasing the wear temperature to 100 1C, the wear rates of AZ91 and the RE-containing alloys decreased by about 58% and 40%, respectively. At higher wear temperatures, the wear of AZ91 alloy increased as a result of softening of b-Mg 17 Al 12 intermetallics resulting in severe plastic deformation and adhesion on the wear surface. However, the wear of the RE containing alloys decreased as the wear temperature increased to 200 1C due to the formation of stable oxide layers on the worn surfaces. The alloy containing 3 wt% RE exhibited the highest wear resistance at the wear temperatures of 150 and 200 1C. Further increase in the wear temperature to 250 1C led to severe plastic deformation and high adhesion of the alloys. & 2013 Elsevier B.V. All rights reserved.

Research paper thumbnail of Modeling the Hot Ductility of AA6061 Aluminum Alloy After Severe Plastic Deformation

Research paper thumbnail of Effect of Ca additions on the microstructure, thermal stability and mechanical properties of a cast AM60 magnesium alloy

Materials Science and Engineering: A, 2010

Research paper thumbnail of Microstructural stability and grain growth kinetics in an extruded fine-grained Mg–Gd–Y–Zr alloy

Journal of Materials Science

The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigate... more The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigated by static annealing in the temperature range of 673–773 K. In addition to the microstructural evolution, textural evolution of the material was also studied during high temperature exposure. The material revealed an unusual basal texture in the extruded condition which was weakened after annealing. The material behavior can be divided into two temperature regimes, namely from 673 to 723 K and from 723 to 773 K. According to the obtained data, although the material shows superior thermal stability in comparison with the conventional Mg alloys, it loses most of its resistance to grain growth at temperatures higher than 673 K. It was observed that although the Mg3(Gd,Y) precipitates have sufficient thermal stability to restrict grain growth, significant grain growth occurs at the highest temperatures where increased mobility of the grain boundaries seems to be dominant. However, there is ...

Research paper thumbnail of Ultra FINE-GRAINEDAZ31 Magnesium Alloy Obtained by a Combination of Grain Refinement and Equal Channel Angular Pressing

International Journal of Modern Physics: Conference Series

Different amounts of Al -5 Ti -1 B master alloy ( TiBAl ) were added to the AZ 31 magnesium alloy... more Different amounts of Al -5 Ti -1 B master alloy ( TiBAl ) were added to the AZ 31 magnesium alloy ( Mg -3 Al -1 Zn -0.2 Mn ) as grain refiner and the resulting microstructure and grain size distributions were studied after extrusion and equal channel angular pressing (ECAP). Results showed that the addition of 0.6% TiBAl had the strongest grain refinement effect, reducing the grain sizes by 54.5 and 48.5% in the extruded and ECAPed conditions, respectively. The observed grain refinement was partly due to the presence of the thermally-stable micron- and submicron-sized particles in the melt which act as nucleation sites during solidification. During the high-temperature extrusion and ECAP processes, dynamic recrystallization (DRX) and grain growth are likely to occur. However, the mentioned particles will help in reducing the grain size by the particle stimulated nucleation (PSN) mechanism. Furthermore, the pinning effect of these particles can oppose grain growth by reducing the gra...

Research paper thumbnail of Effect of isothermal aging on room temperature impression creep of lead free Sn–9Zn and Sn–8Zn–3Bi solders

Materials Science and Technology

Research paper thumbnail of Effect of Sb addition on the tensile deformation behavior of lead-free Sn–3.5Ag solder alloy

Materials & Design

... Short Communication. Effect of Sb addition on the tensile deformation behavior of lead-free S... more ... Short Communication. Effect of Sb addition on the tensile deformation behavior of lead-free Sn–3.5Ag solder alloy. R. Mahmudi Corresponding Author Contact Information , a , E-mail The Corresponding Author and S. Mahin-Shirazi a. ...

Research paper thumbnail of Constitutive Analysis and Hot Deformation Behavior of Fine-Grained Mg-Gd-Y-Zr Alloys

Metallurgical and Materials Transactions A

Research paper thumbnail of Evolutions of mechanical properties of AISI 304L stainless steel under shear loading

Materials Science and Engineering: A, 2020

Research paper thumbnail of Mechanical response of a metastable austenitic stainless steel under different deformation modes

Materials Science and Technology, 2021

The deformation behaviour of AISI 304L stainless steel was examined under uniaxial tension and sh... more The deformation behaviour of AISI 304L stainless steel was examined under uniaxial tension and shear deformation modes in the temperature range of 0–500°C. A linear relationship between the tensile and shear yield stresses was observed over the whole temperature range, which was in a good agreement with the predictions of the von-Mises criterion. The relationship between the ultimate shear and tensile strength values, however, showed three distinct temperature-dependent regimes. In the temperature ranges corresponding to the transformation-induced plasticity effect and the dynamic strain aging phenomenon, a deviation from the expected behaviour was observed, which was related to the dependency of these phenomena on the loading mode.

Research paper thumbnail of Effect of texture and twinning on mechanical properties and corrosion behavior of an extruded biodegradable Mg–4Zn alloy

Journal of Magnesium and Alloys, 2019

Research paper thumbnail of Enhanced microstructural stability and mechanical properties of the Ag-containing Mg–Gd–Y alloys

Journal of Magnesium and Alloys, 2020

Research paper thumbnail of Hot deformation behavior of an extruded AZ31 alloy doped with rare-earth elements

Journal of Alloys and Compounds, 2021

Research paper thumbnail of Tailoring the texture of an extruded Mg sheet through constrained groove pressing for achieving low mechanical anisotropy and high yield strength

Research paper thumbnail of Microstructure characterization and high-temperature shear strength of the Mg–10Gd–3Y–1.2Zn–0.5Zr alloy in the as-cast and aged conditions

Journal of Alloys and Compounds, 2015

Research paper thumbnail of Enhanced superplasticity in an extruded high strength Mg–Gd–Y–Zr alloy with Ag addition

Journal of Alloys and Compounds, 2015

Research paper thumbnail of Enhanced creep properties of a cast Mg–5Sn alloy subjected to aging-treatment

Materials Science and Engineering: A, 2010

The microstructure and impression creep behavior of the Mg–5Sn alloy are studied in the as-cast a... more The microstructure and impression creep behavior of the Mg–5Sn alloy are studied in the as-cast and aged conditions. Impression creep tests were performed in the temperature range 423–498K and under punching stresses in the range 125–400MPa. Analysis of the data showed that for all loads and temperatures, the creep resistance of the aged alloys was much better than that of

Research paper thumbnail of Surface roughening during uniaxial and equi-biaxial stretching of 70-30 brass sheets

Journal of Materials Processing Technology, 1998

The surface roughening behaviour of 70-30 brass sheets was investigated under uniaxial and equi-b... more The surface roughening behaviour of 70-30 brass sheets was investigated under uniaxial and equi-biaxial stress states. Attention was focused on two main industrial conditions of the materials, these being representative of the materials that could be processed by the commercial batch-annealing process (slow heating, long time) or by a continuous annealing process (fast heating, short time). These two regimes produced

Research paper thumbnail of Hot deformation constitutive analysis and processing maps of extruded Mg–Gd binary alloys

Journal of Materials Research and Technology, 2020

Research paper thumbnail of Impression creep of Sn–40Pb–2·5Sb peritectic solder alloy

Materials Science and Technology, 2005

Research paper thumbnail of Effect of rare earth elements addition on the tribological behavior of AZ91D magnesium alloy at elevated temperatures

Wear, 2013

ABSTRACT a b s t r a c t The effect of 1, 2, and 3 wt% of lanthanum-base rare earth (RE) element ... more ABSTRACT a b s t r a c t The effect of 1, 2, and 3 wt% of lanthanum-base rare earth (RE) element additions on the wear behavior of AZ91 alloy was investigated under a normal load of 20 N at the wear temperatures of 25–250 1C. The wear tests were carried out using a pin-on-disk tribometer at a sliding speed of 0.4 ms À 1 for a sliding distance of 1000 m. The results showed that there was no change in the wear rate of the alloys at the wear temperature of 25 1C. By increasing the wear temperature to 100 1C, the wear rates of AZ91 and the RE-containing alloys decreased by about 58% and 40%, respectively. At higher wear temperatures, the wear of AZ91 alloy increased as a result of softening of b-Mg 17 Al 12 intermetallics resulting in severe plastic deformation and adhesion on the wear surface. However, the wear of the RE containing alloys decreased as the wear temperature increased to 200 1C due to the formation of stable oxide layers on the worn surfaces. The alloy containing 3 wt% RE exhibited the highest wear resistance at the wear temperatures of 150 and 200 1C. Further increase in the wear temperature to 250 1C led to severe plastic deformation and high adhesion of the alloys. & 2013 Elsevier B.V. All rights reserved.

Research paper thumbnail of Modeling the Hot Ductility of AA6061 Aluminum Alloy After Severe Plastic Deformation

Research paper thumbnail of Effect of Ca additions on the microstructure, thermal stability and mechanical properties of a cast AM60 magnesium alloy

Materials Science and Engineering: A, 2010

Research paper thumbnail of Microstructural stability and grain growth kinetics in an extruded fine-grained Mg–Gd–Y–Zr alloy

Journal of Materials Science

The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigate... more The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigated by static annealing in the temperature range of 673–773 K. In addition to the microstructural evolution, textural evolution of the material was also studied during high temperature exposure. The material revealed an unusual basal texture in the extruded condition which was weakened after annealing. The material behavior can be divided into two temperature regimes, namely from 673 to 723 K and from 723 to 773 K. According to the obtained data, although the material shows superior thermal stability in comparison with the conventional Mg alloys, it loses most of its resistance to grain growth at temperatures higher than 673 K. It was observed that although the Mg3(Gd,Y) precipitates have sufficient thermal stability to restrict grain growth, significant grain growth occurs at the highest temperatures where increased mobility of the grain boundaries seems to be dominant. However, there is ...

Research paper thumbnail of Ultra FINE-GRAINEDAZ31 Magnesium Alloy Obtained by a Combination of Grain Refinement and Equal Channel Angular Pressing

International Journal of Modern Physics: Conference Series

Different amounts of Al -5 Ti -1 B master alloy ( TiBAl ) were added to the AZ 31 magnesium alloy... more Different amounts of Al -5 Ti -1 B master alloy ( TiBAl ) were added to the AZ 31 magnesium alloy ( Mg -3 Al -1 Zn -0.2 Mn ) as grain refiner and the resulting microstructure and grain size distributions were studied after extrusion and equal channel angular pressing (ECAP). Results showed that the addition of 0.6% TiBAl had the strongest grain refinement effect, reducing the grain sizes by 54.5 and 48.5% in the extruded and ECAPed conditions, respectively. The observed grain refinement was partly due to the presence of the thermally-stable micron- and submicron-sized particles in the melt which act as nucleation sites during solidification. During the high-temperature extrusion and ECAP processes, dynamic recrystallization (DRX) and grain growth are likely to occur. However, the mentioned particles will help in reducing the grain size by the particle stimulated nucleation (PSN) mechanism. Furthermore, the pinning effect of these particles can oppose grain growth by reducing the gra...

Research paper thumbnail of Effect of isothermal aging on room temperature impression creep of lead free Sn–9Zn and Sn–8Zn–3Bi solders

Materials Science and Technology

Research paper thumbnail of Effect of Sb addition on the tensile deformation behavior of lead-free Sn–3.5Ag solder alloy

Materials & Design

... Short Communication. Effect of Sb addition on the tensile deformation behavior of lead-free S... more ... Short Communication. Effect of Sb addition on the tensile deformation behavior of lead-free Sn–3.5Ag solder alloy. R. Mahmudi Corresponding Author Contact Information , a , E-mail The Corresponding Author and S. Mahin-Shirazi a. ...

Research paper thumbnail of Constitutive Analysis and Hot Deformation Behavior of Fine-Grained Mg-Gd-Y-Zr Alloys

Metallurgical and Materials Transactions A