Alireza Rezaei

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School of Metallurgy and Materials Engineering
University of Tehran

Alireza Rezaei


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https://researchid.co/a.rezaei

EDUCATION

PhD in Metallurgy and Materials Engineering
MSc in Materials Science and Engineering
BSc in Materials Science and Engineering

RESEARCH, TEACHING, or OTHER INTERESTS

Metals and Alloys, Materials Science
12

Scopus Publications

236

Scholar Citations

9

Scholar h-index

9

Scholar i10-index

Scopus Publications

  • In situ EBSD analysis of the deformation mechanisms of a Zn-1wt%Mg alloy manufactured by laser powder bed fusion
    Nafiseh Mollaei, Alireza Rezaei, Biaobiao Yang, Mónica Echeverry-Rendón, Jon M. Molina-Aldareguía, Federico Sket, Javier LLorca
    Acta Materialia, 2026
    The deformation mechanisms of a Zn-1wt.% Mg alloy fabricated by laser powder-bed fusion were investigated by in situ mechanical tests within the scanning electron microscope combined with electron backscatter diffraction. Fully dense samples with a relative density of ∼99.95% were produced using optimized processing parameters. The microstructure consisted of fine equiaxed α-Zn grains (average size ∼2.8 µm) with a weak crystallographic texture, along with a eutectic network of α-Zn + Mg₂Zn₁₁ located primarily at grain boundaries. Plastic deformation was dominated by <a> basal slip, with an increasing contribution of <c+a> pyramidal II slip at higher strain levels, particularly in grains that had already activated basal slip. Twinning played a negligible role, and grain boundary sliding was suppressed due to the continuous eutectic phase at the grain boundaries. Schmid factor analysis confirmed that both <a> and <c+a> slip systems followed the Schmid law. Large lattice misorientations developed in the grains, leading to a rapid increase in the density of geometrically necessary dislocations, which triggered dynamic recrystallization at low strains (6.5%). Dynamic recrystallization, driven by progressive lattice rotation and grain fragmentation, hindered the strain hardening. Fracture occurred at low strains (< 10%) and was triggered by the presence of oxide particles that acted as crack initiation sites. These findings provide insights into the deformation behavior of additively manufactured Zn-based alloys and provide valuable guidance for the development of next-generation biodegradable Zn implants with enhanced mechanical performance.
  • Ascertaining the plastic deformation mechanisms of polycrystalline extruded Zn through in situ SEM/EBSD mechanical tests
    Alireza Rezaei, Nafiseh Mollaei, Maral Sarebanzadeh, Biaobiao Yang, Seyed Mahmood Fatemi, Javier LLorca
    International Journal of Plasticity, 2026
    • The sequence of plastic deformation mechanisms of polycrystalline Zn was reported by means of in situ mechanical tests in the SEM. • Plastic deformation was initially accommodated by <a> basal slip, leading to hardening, and grain boundary sliding. • Slip transfer at grain boundaries was never found because of grain boundary sliding. • <c+a> pyramidal II slip was also found but <c+a> pyramidal dislocations were dissociated into the basal plane and became sessile. • The contribution of twinning to the total strain was limited (around 11% when the applied strain was 16.7%). • •The strain hardening rate decreased sharply beyond 6.7% because of grain boundary slding and compression twinning The plastic deformation micro-mechanisms of extruded pure Zn deformed in tension along the extrusion direction were investigated by means of in situ scanning electron microscopy (SEM) integrated with electron back-scatter diffraction (EBSD). Plastic deformation began with the activation of < a > basal slip in grains with the highest Schmid factor while the incompatibility of deformation between neighbour grains was accommodated by grain boundary sliding. The geometrically necessary dislocation density increased sharply from 1.53 × 10 13 m⁻² to 9.03 × 10 13 m⁻² when applied strain reached 6.7%, and this increase coincides with the strong initial strain hardening region. The incompatibility of deformation between neighbour grains was accommodated by grain boundary sliding at strains above 3.3%, which somehow limited the strain hardening rate. Evidence of < c+a > pyramidal II slip was also found through slip trace analysis from the early stages of deformation, i.e. 1.6% strain, but it was always limited to a small fraction of suitably oriented grains. Moreover, transmission electron microscopy observations showed that many < c+a > pyramidal dislocations were dissociated into the basal plane and became sessile. {10 1 ¯ 2}<10 1 ¯ 1 ¯ > compression twins were nucleated at 3.3% strain and the fraction of grains undergoing twinning as well as the area fraction of twins increased proportionally to the applied strain. Twinning was favoured by the fiber texture and the twin variant with the highest Schmid factor was primarily activated in each grain. The contribution of twinning to the total strain was limited (around 11% when the applied strain was 16.7%). The strain hardening rate decreased sharply beyond 6.7% and the hardening contribution of basal slip was balanced by grain boundary slding and compression twinning. Finally, a high fraction of sub-grain boundaries that trigger recrystallization at larger strains ws found at 16.7%. These observations reveal the sequence and interaction of plastic deformation mechanisms in Zn, which may help design novel Zn alloys with improved mechanical properties.
  • Dynamic recrystallization and strengthening mechanisms in a magnesium alloy processed by severe plastic deformation
    Alireza Rezaei, Reza Mahmudi, Roland E. Logé
    Journal of Magnesium and Alloys, 2025
    An extruded Mg-Gd-Y-Ag alloy was subjected to simple shear extrusion (SSE) at 280 °C to obtain a refined microstructure, with a focus on examining microstructural evolutions through detailed EBSD analysis and TEM. The EBSD results revealed that the microstructures at the early stages of deformation contained large deformed grains with a significant fraction of low angle grain boundaries developed through dynamic recovery. Continuous dynamic recrystallization (CDRX) was dominant as deformation proceeded. Two kinds of CDRX grains were recognized considering their locations; “GB-type” grains, which formed in the vicinity of the pre-existing boundaries of the deformed grains, and “Core-type” grains, emerging within the interior areas. The EBSD exhibited pronounced misorientation gradients in the areas adjacent to pre-existing boundaries, and severe fragmentation into subgrains. At larger strains, the density of subgrain boundaries declined due to the massive progress of discontinuous dynamic recrystallization (DDRX). TEM investigations confirmed the emergence of globular Mg 5 Gd-type nano-particles exclusively within the DRXed areas through dynamic precipitation, and the precipitation of nano-sized βʹ -phase, mainly within the larger deformed grains. Basal texture components of “type-I” and “type-II” were identified following 6 SSE passes. In the former case, the basal planes rearranged parallel to the shear planes with their poles aligned along the normal direction (ND) as a result of the activity of the basal slip system. In contrast, in the latter scenario, the basal poles were parallel to the transverse direction (TD) due to the 90° rotation of the workpiece between consecutive passes. The results of shear punch testing (SPT) indicated an increase in the shear strength, as the number of passes in SSE increased from 1 to 6. The improved mechanical response of the alloys after SSE was ascribed to various strengthening mechanisms, including the influence of low-angle grain boundaries (LAGBs), precipitation hardening and grain boundary strengthening.
  • Superplastic behavior of a fine-grained Mg−Gd−Y−Ag alloy processed by equal channel angular pressing
    A. Rezaei, R. Mahmudi, R.E. Logé
    Journal of Magnesium and Alloys, 2023
    An extruded Mg−6Gd−3Y−1.5Ag (wt %) alloy was processed by 6 passes of equal channel angular pressing (ECAP) at 553 K using route Bc to refine the microstructure. Electron back-scattered diffraction (EBSD) analysis showed a fully recrystallized microstructure for the extruded alloy with a mean grain size of 8.6 µm. The microstructure of the ECAP-processed alloy was uniformly refined through dynamic recrystallization (DRX). This microstructure contained fine grains with an average size of 1.3 µm, a high fraction of high angle grain boundaries (HAGBs), and nano-sized Mg5Gd-type particles at the boundaries of the DRXed grains, detected by transmission electron microscopy (TEM). High-temperature shear punch testing (SPT) was used to evaluate the superplastic behavior of both the extruded and ECAP-processed alloys by measuring the strain rate sensitivity (SRS) index (m-value). While the highest m-value for the extruded alloy was measured to be 0.24 at 673 K, the ECAP-processed alloy exhibited much higher m-values of 0.41 and 0.52 at 598 and 623 K, respectively, delineating the occurrence of superplastic flow. Based on the calculated average activation energy of 118 kJ mol−1 and m-values close to 0.5, the deformation mechanism for superplastic flow at the temperatures of 598 and 623 K for the ECAP-processed alloys was recognized to be grain boundary sliding (GBS) assisted by grain boundary diffusion.
  • Microstructural and hardness homogeneity in an Mg–Gd−Y–Ag alloy processed by simple shear extrusion
    A. Rezaei, R. Mahmudi, R.E. Logé
    Materials Science and Engineering A, 2023
  • Simple shear extrusion versus equal channel angular pressing: A comparative study on the microstructure and mechanical properties of an Mg alloy
    A. Rezaei, R. Mahmudi, C. Cayron, R.E. Logé
    Journal of Magnesium and Alloys, 2023
    Two severe plastic deformation (SPD) techniques of simple shear extrusion (SSE) and equal channel angular pressing (ECAP) were employed to process an extruded Mg−6Gd−3Y−1.5Ag (wt%) alloy at 553 K for 1, 2, 4 and 6 passes. The microstructural evolutions were studied by electron back scattered diffraction (EBSD) analysis and transmission electron microscopy (TEM). The initial grain size of 7.5 µm in the extruded alloy was reduced to about 1.3 µm after 6 SPD passes. Discontinuous dynamic recrystallization was suggested to be operative in both SSE and ECAP, with also a potential contribution of continuous dynamic recrystallization at the early stages of deformation. The difference in the shear strain paths of the two SPD techniques caused different progression rate of dynamic recrystallization (DRX), so that the alloys processed by ECAP exhibited higher fractions of recrystallization and high angle grain boundaries (HAGBs). It was revealed that crystallographic texture was also significantly influenced by the difference in the strain paths of the two SPD methods, where dissimilar basal plane texture components were obtained. The compression tests, performed along extrusion direction (ED), indicated that the compressive yield stress (CYS) and ultimate compressive strength (UCS) of the alloys after both SEE and ECAP augmented continuously by increasing the number of passes. ECAP-processed alloys had lower values of CYS and UCS compared to their counterparts processed by SSE. This difference in the mechanical responses was attributed to the different configurations of basal planes with respect to the loading direction (ED) of each SPD technique.
  • Compressive properties of a severely deformed fine-grained Mg−6Gd−3Y alloy
    A. Rezaei, R. Mahmudi, R.E. Logé
    Materials Science and Engineering A, 2023
  • Microstructural evolution and superplastic behavior of a fine-grained Mg−Gd−Y−Ag alloy processed by simple shear extrusion
    A. Rezaei, R. Mahmudi, C. Cayron, R. Loge
    Materials Science and Engineering A, 2021
  • Superplastic behavior of a severely deformed Mg–6Gd−3Y−0.5Ag alloy
    A. Rezaei, R. Mahmudi, C. Cayron, R.E. Loge
    Materials Science and Engineering A, 2021
  • Effect of Ag Addition on the Hot Deformation, Constitutive Equations and Processing Maps of a Hot Extruded Mg-Gd-Y Alloy
    A. Rezaei, R. Mahmudi, R. Loge
    Metallurgical and Materials Transactions A Physical Metallurgy and Materials Science, 2020
  • Investigating the effect of heat treatment on the fracture toughness of a hot extruded Al–Ti composite produced by powder metallurgy route
    Alireza Rezaei, Hamid Reza Madaah Hosseini
    Materials Science and Engineering A, 2020
  • Evolution of microstructure and mechanical properties of Al-5 wt% Ti composite fabricated by P/M and hot extrusion: Effect of heat treatment
    Alireza Rezaei, Hamid Reza Madaah Hosseini
    Materials Science and Engineering A, 2017

RECENT SCHOLAR PUBLICATIONS

  • In situ EBSD analysis of the deformation mechanisms of a Zn-1wt% Mg alloy manufactured by laser powder bed fusion
    N Mollaei, A Rezaei, B Yang, M Echeverry, JM Molina-Aldreguía, F Sket, ...
    Acta Materialia, 122225 , 2026
    2026
  • Ascertaining the plastic deformation mechanisms of polycrystalline extruded Zn through in situ SEM/EBSD mechanical tests
    A Rezaei, N Mollaei, M Sarebanzadeh, B Yang, SM Fatemi, J LLorca
    International Journal of Plasticity, 104548 , 2025
    2025
    Citations: 10
  • Dynamic recrystallization and strengthening mechanisms in a magnesium alloy processed by severe plastic deformation
    A Rezaei, R Mahmudi, RE Logé
    Journal of Magnesium and Alloys , 2025
    2025
    Citations: 8
  • Superplastic behavior of a fine-grained Mg− Gd− Y− Ag alloy processed by equal channel angular pressing
    A Rezaei, R Mahmudi, RE Logé
    Journal of Magnesium and Alloys 11 (10), 3815-3828 , 2023
    2023
    Citations: 22
  • Microstructural and hardness homogeneity in an Mg–Gd− Y–Ag alloy processed by simple shear extrusion
    A Rezaei, R Mahmudi, RE Logé
    Materials Science and Engineering: A 876, 145159 , 2023
    2023
    Citations: 13
  • Simple shear extrusion versus equal channel angular pressing: A comparative study on the microstructure and mechanical properties of an Mg alloy
    A Rezaei, R Mahmudi, C Cayron, RE Logé
    Journal of Magnesium and Alloys 11 (5), 1769-1790 , 2023
    2023
    Citations: 33
  • Compressive properties of a severely deformed fine-grained Mg− 6Gd− 3Y alloy
    A Rezaei, R Mahmudi, RE Logé
    Materials Science and Engineering: A 868, 144769 , 2023
    2023
    Citations: 6
  • Microstructural evolution and superplastic behavior of a fine-grained Mg− Gd− Y− Ag alloy processed by simple shear extrusion
    A Rezaei, R Mahmudi, C Cayron, R Loge
    Materials Science and Engineering: A 806, 140803 , 2021
    2021
    Citations: 42
  • Superplastic behavior of a severely deformed Mg–6Gd− 3Y− 0.5 Ag alloy
    A Rezaei, R Mahmudi, C Cayron, RE Loge
    Materials Science and Engineering: A 802, 140616 , 2021
    2021
    Citations: 35
  • Effect of Ag addition on the hot deformation, constitutive equations and processing maps of a hot extruded Mg-Gd-Y alloy
    A Rezaei, R Mahmudi, R Loge
    Metallurgical and Materials Transactions A 51 (10), 5139-5153 , 2020
    2020
    Citations: 17
  • Investigating the effect of heat treatment on the fracture toughness of a hot extruded Al–Ti composite produced by powder metallurgy route
    A Rezaei, HRM Hosseini
    Materials Science and Engineering: A 771, 138573 , 2020
    2020
    Citations: 16
  • Evolution of microstructure and mechanical properties of Al-5 wt% Ti composite fabricated by P/M and hot extrusion: Effect of heat treatment
    A Rezaei, HRM Hosseini
    Materials Science and Engineering: A 689, 166-175 , 2017
    2017
    Citations: 34

MOST CITED SCHOLAR PUBLICATIONS

  • Microstructural evolution and superplastic behavior of a fine-grained Mg− Gd− Y− Ag alloy processed by simple shear extrusion
    A Rezaei, R Mahmudi, C Cayron, R Loge
    Materials Science and Engineering: A 806, 140803 , 2021
    2021
    Citations: 42
  • Superplastic behavior of a severely deformed Mg–6Gd− 3Y− 0.5 Ag alloy
    A Rezaei, R Mahmudi, C Cayron, RE Loge
    Materials Science and Engineering: A 802, 140616 , 2021
    2021
    Citations: 35
  • Evolution of microstructure and mechanical properties of Al-5 wt% Ti composite fabricated by P/M and hot extrusion: Effect of heat treatment
    A Rezaei, HRM Hosseini
    Materials Science and Engineering: A 689, 166-175 , 2017
    2017
    Citations: 34
  • Simple shear extrusion versus equal channel angular pressing: A comparative study on the microstructure and mechanical properties of an Mg alloy
    A Rezaei, R Mahmudi, C Cayron, RE Logé
    Journal of Magnesium and Alloys 11 (5), 1769-1790 , 2023
    2023
    Citations: 33
  • Superplastic behavior of a fine-grained Mg− Gd− Y− Ag alloy processed by equal channel angular pressing
    A Rezaei, R Mahmudi, RE Logé
    Journal of Magnesium and Alloys 11 (10), 3815-3828 , 2023
    2023
    Citations: 22
  • Effect of Ag addition on the hot deformation, constitutive equations and processing maps of a hot extruded Mg-Gd-Y alloy
    A Rezaei, R Mahmudi, R Loge
    Metallurgical and Materials Transactions A 51 (10), 5139-5153 , 2020
    2020
    Citations: 17
  • Investigating the effect of heat treatment on the fracture toughness of a hot extruded Al–Ti composite produced by powder metallurgy route
    A Rezaei, HRM Hosseini
    Materials Science and Engineering: A 771, 138573 , 2020
    2020
    Citations: 16
  • Microstructural and hardness homogeneity in an Mg–Gd− Y–Ag alloy processed by simple shear extrusion
    A Rezaei, R Mahmudi, RE Logé
    Materials Science and Engineering: A 876, 145159 , 2023
    2023
    Citations: 13
  • Ascertaining the plastic deformation mechanisms of polycrystalline extruded Zn through in situ SEM/EBSD mechanical tests
    A Rezaei, N Mollaei, M Sarebanzadeh, B Yang, SM Fatemi, J LLorca
    International Journal of Plasticity, 104548 , 2025
    2025
    Citations: 10
  • Dynamic recrystallization and strengthening mechanisms in a magnesium alloy processed by severe plastic deformation
    A Rezaei, R Mahmudi, RE Logé
    Journal of Magnesium and Alloys , 2025
    2025
    Citations: 8
  • Compressive properties of a severely deformed fine-grained Mg− 6Gd− 3Y alloy
    A Rezaei, R Mahmudi, RE Logé
    Materials Science and Engineering: A 868, 144769 , 2023
    2023
    Citations: 6
  • In situ EBSD analysis of the deformation mechanisms of a Zn-1wt% Mg alloy manufactured by laser powder bed fusion
    N Mollaei, A Rezaei, B Yang, M Echeverry, JM Molina-Aldreguía, F Sket, ...
    Acta Materialia, 122225 , 2026
    2026