Search

Your search keyword '"Azzeddine, Hiba"' showing total 154 results
Start Over Author "Azzeddine, Hiba"
154 results on '"Azzeddine, Hiba"'

34. Estimating dislocation density from electron backscatter diffraction data for an AZ31/Mg-0.6Gd hybrid alloy fabricated by high-pressure torsion.

Author

Baudin, Thierry, Azzeddine, Hiba, Brisset, François, Huang, Yi, and Langdon, Terence G.

Subjects
*DISLOCATION density, *ELECTRON diffraction, *HYBRID materials, *TORSION, *ALLOYS, *ELECTRON density
Abstract

The Geometrically Necessary Dislocation (GND) density was estimated from Electron Backscatter Diffraction (EBSD) data for an AZ31/Mg-0.6Gd (wt.%) hybrid material fabricated by high-pressure torsion (HPT) at room temperature through an equivalent strain range of ϵeq = 0.3–144 using Kernel Average Misorientation (KAM) and the Nye tensor approaches. The results show that generally the GND densities are significant at the beginning of the deformation (ϵeq = 0.3) and decrease in both alloys when ϵeq increases. The Mg-0.6Gd alloy exhibits a lower GND density due to rapid dynamic recrystallization. These results were compared to the GND densities measured in AZ31 and Mg-0.6Gd mono-materials processed separately by HPT under the same experimental conditions. In these mono-materials the GND densities increase with increasing equivalent strain up to 7 and then decrease with further straining. The Mg-0.6Gd and AZ31 regions of the hybrid material exhibit higher GND densities than the mono-materials particularly at low strain where the disc thickness and the bonding of the AZ31/Mg-0.6Gd interfaces cause more deformation heterogeneity in the hybrid material. It is shown that the GND density evolution as a function of ϵeq has the same tendency for the KAM and the Nye approaches but the average values are significantly higher with the Nye approach. An analysis suggests that the Nye approach overestimates the GND density of the Mg-based alloys. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

37. Grain growth activation energy of ECAP-processed Mg-Ce alloy: Effect of deformation temperature

Author

Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Azzeddine, Hiba, Sadi, Salaheddine, Hanna, Abdelkader, Baudin, Thierry, Brisset, François, Cabrera Marrero, José M., Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Azzeddine, Hiba, Sadi, Salaheddine, Hanna, Abdelkader, Baudin, Thierry, Brisset, François, and Cabrera Marrero, José M.

Abstract

In the present work, the grain growth activation energy, Q was evaluated in a Mg-0.3Ce (wt%) alloy after equal-channel angular pressing (ECAP) processing via route Bc for 4 passes at 300 and 350 °C and followed by isochronal annealing at 150, 250, 350, and 450 °C for 2 h. The results demonstrated that Q depends strongly on the deformation processing. The Q value was equal to 111.4 ± 5.7 kJ/mol for the sample ECAP-processed at 300 °C. While the sample ECAP-processed at 350 °C shows the presence of two different Q values depending on the annealing temperature, QI = 26.5 ± 3.4 kJ/mol in the low-temperature range (150–350 °C) and QII = 120.7 kJ/mol in the high-temperature range (350–450 °C). This behaviour was attributed to the resulting deformation microstructure and the occurrence of dynamic grain growth during ECAP processing at 350 °C., Peer Reviewed, Postprint (author's final draft)

Published
2023

44. Microstructure and texture evolution of ECAP-processed Mg-Ce alloy during isothermal annealing

Author

Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Sadi, Salaheddine, Hanna, Abdelkader, Baudin, Thierry, Brisset, François, Cabrera Marrero, José M., Azzeddine, Hiba, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Sadi, Salaheddine, Hanna, Abdelkader, Baudin, Thierry, Brisset, François, Cabrera Marrero, José M., and Azzeddine, Hiba

Abstract

Static recrystallization and grain growth behaviors were investigated in Mg-0.3Ce (wt%) alloy processed by equal-channel angular pressing (ECAP) for N = 1 (eeq = 0.9), 2 (eeq = 1.9), and 4 (eeq = 3.9) passes at 300 °C using route Bc and annealed at 450 °C for 5, 30, 60, and 180 min. The results demonstrated that the annealed microstructure and texture are strongly related to the strain level, second particles distribution, and fraction of dynamic recrystallization (DRX) during ECAP. At low strain (1 ECAP pass), the microstructure was very heterogeneous and the texture development changed with increasing annealing time due to the absence of sufficient recrystallization nucleation sites and pinning effect of second particles. At medium strain (2 ECAP passes), the microstructure was homogeneous, however, the texture was unstable mainly due to the limited DRX during ECAP processing leading to the preferred grain growth. At high strain (4 ECAP passes), the microstructure was homogeneous and the texture was retained throughout the entire annealing duration due to the significant amount of DRX., Peer Reviewed, Postprint (author's final draft)

Published
2022

45. Investigation of Microstructure and Texture Evolution in an AZ31/Mg–Gd Alloy Hybrid Metal Fabricated by High‐Pressure Torsion.

Author

Ould Mohamed, Ouarda, Azzeddine, Hiba, Huang, Yi, Baudin, Thierry, Bazarnik, Piotr, Brisset, François, Kawasaki, Megumi, and Langdon, Terence G.

Subjects
HYBRID materials, ALLOY texture, ALLOYS, MICROSTRUCTURE, RECRYSTALLIZATION (Metallurgy)
Abstract

High‐pressure torsion (HPT) processing is successfully applied to fabricate a novel hybrid material from separate discs of AZ31 (Mg–3Al–1Zn, wt%) and Mg–0.6Gd (wt%) alloys by straining through numbers of rotations, N, of 1/4, 1/2, 5, 10, and 20 turns at room temperature. The microstructure and texture are investigated near the bonding interface through the disc diameter using electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The microstructure exhibits two grain refinement regimes with the first occurring during an equivalent strain range, εeq, of ≈0.3–72 and the second during εeq from ≈72 to 517. The general texture changes from B‐fiber to Y‐fiber and C2‐fiber through the HPT processing. The resultant microstructures and textures of this hybrid alloy are examined separately for the AZ31 and Mg‐0.6Gd alloys and found controlled by the presence of twinning, slip systems, and second phases and the occurrence of different dynamic recrystallization mechanisms. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

49. Effect of ECAP and subsequent annealing on microstructure, texture, and microhardness of a AA6060 aluminum alloy

Author

Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. PROCOMAME - Processos de Conformació de Materials Metàl·lics, Khelfa, T., Azzeddine, Hiba, Muñoz Bolaños, J.A., Cabrera Marrero, José M., Brisset, François, Helbert, Anne-Laure, Baudin, Thierry, Khitouni, Mohamed, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. PROCOMAME - Processos de Conformació de Materials Metàl·lics, Khelfa, T., Azzeddine, Hiba, Muñoz Bolaños, J.A., Cabrera Marrero, José M., Brisset, François, Helbert, Anne-Laure, Baudin, Thierry, and Khitouni, Mohamed

Abstract

AA6060 aluminum alloy was subjected to severe plastic deformation through equal-channel angular pressing (ECAP) up to 8 passes via route BC. ECAPed samples isochronally annealed for 1 hour at a temperature range of 150-450 °C. The microstructure and texture of the studied material were evaluated by electron backscatter diffraction, and the microhardness was characterized by Vickers microhardness testing. It was found that shearing texture is typically enhanced after ECAP processing. Grain size and grain growth kinetics were also studied. ECAP led to a substantial rise in hardness, with stability following 4 passes. Microstructures and material properties were relatively stable up to annealing temperatures of 150 °C. Some sub-micrometer grains were kept in the 8 passes sample to annealing temperatures of 300 °C. Annealing at elevated temperature resulted in a reduction in hardness leading to a rise in grain size and a decrease in dislocation density. After annealing temperature up to 450 °C, the texture index reveals a tendency to the texture weakening and randomization. The activation energy required for the grain growth of the AA6060 alloy was exceptionally low above 300 °C., Peer Reviewed, Postprint (author's final draft)

Published
2021

50. Characterization of microstructure and texture of binary Mg-Ce alloy processed by equal channel angular pressing

Author

Universitat Politècnica de Catalunya. Unitat Transversal de Gestió del Campus Diagonal-Besòs, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. PROCOMAME - Processos de Conformació de Materials Metàl·lics, Sadi, Salaheddine, Hanna, Abdelkader, Azzeddine, Hiba, Casas Quesada, Casimir, Baudin, Thierry, Helbert, Anne-Laure, Brisset, François, Cabrera Marrero, José M., Universitat Politècnica de Catalunya. Unitat Transversal de Gestió del Campus Diagonal-Besòs, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. PROCOMAME - Processos de Conformació de Materials Metàl·lics, Sadi, Salaheddine, Hanna, Abdelkader, Azzeddine, Hiba, Casas Quesada, Casimir, Baudin, Thierry, Helbert, Anne-Laure, Brisset, François, and Cabrera Marrero, José M.

Abstract

The characterization of microstructure and texture development of binary Mg-0.3Ce (wt%) after equal-channel angular pressing (ECAP) processing via route Bc at 300 and 350 °C through 4 passes were investigated using electron backscatter diffraction (EBSD) measurements. The results demonstrated an effective grain refinement from millimeter range to 6.7 and 8.3 µm obtained after 4 passes at 300 and 350 °C, respectively. The grain refinement was obtained through dynamic recrystallization (DRX). At 300 °C, DRX occurred at low strain by twin-induced dynamic recrystallization (TDRX) and particle stimulated nucleation (PSN) mechanism and then converted with increasing strain to sub-grain development (SD) and grain boundary bulging dynamic recrystallization (GBBDRX). Besides, grain growth occurred during processing at 350 °C. The texture development strongly depends on the strain level, deformation temperature and DRX mechanisms. At 300 °C, a typical basal texture with a deviation of 40° towards extrusion direction was formed gradually up to 4 passes while a completely different texture was formed at 350 °C due to the large grain size., Peer Reviewed, Postprint (author's final draft)

Published
2021

Catalog

Books, media, physical & digital resources
See catalog results