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Papers by Abdelali Samiri
Materials today communications, Jul 1, 2024
In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metall... more In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metallic glass (MG) and three Mg-Al based nanoscale crystal/glass nanolaminates (NCGNLs) during crack propagation under tension loading are investigated using Molecular Dynamics (MD) simulations. The results observed in NCGNLs are compared with those related to pure MG to determine the effect of the NCGNLs on material strength and fracture toughness. The results show that the NCGNLs have a higher Young's modulus (E) and ultimate tensile strength (UTS) compared to pure MG. Which mean that the heterogeneous interphase between the crystalline layers and the amorphous pure glass behaves as the barriers behind the plastic deformation. Nano-patterning involving Aluminum (Al) and Magnesium (Mg) positively affects the fracture toughness of the material, while Mg 25 Al 75 / glass NCGNLs was found to be the most brittle and most prone to failure under tensile strain. The Al/glass NCGNLs is found to be the most ductile and able to withstand higher levels of strain before cracking. The simulations also reveal the deformation mechanisms at the atomic level, showing the nucleation/emission of dislocations types, twin boundary (TB), and stacking faults (SF) from the amorphous layer and their propagation to the Mg and Al crystal phases, respectively. These findings provide valuable insights into the mechanical properties of Mg-Al based nanolaminates and can inform the design of stronger and more durable materials.
We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocompo... more We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocomposites (NCs) using molecular dynamics (MD) simulations within the framework of the Embedded Atom method (EAM). In terms of mechanical properties, metallic glass (MGs) are characterized by high performance, such as high yield strength and high strength, long-range atomic order is the main feature that links these mechanical properties to the structure of MGs. In the present work, the atomic structural characteristic of Al-MG is studied via several quantities such as radial distribution function (RDF), Voronoi tessellation analysis (VTA) and coordination number distribution (CN). Generally, the splitting of the second RDF peak during quenching confirmed the formation of Al-MG. The results of the application of a uniaxial tensile stress on the Al-MG samples and the NCs at 300 K with a strain rate of the order of 5. 10 8 s − 1 showed that the mechanical properties (Young's modulus, ultimate tensile strength, elastic limit, etc.) are improved by the reinforcement of the Al-MG matrix with fibers (cylinder) of crystalline nickel compared to that of-monatomic Al-MG. In general, it is observed that the ultimate tensile strength and Young's modulus increase with the increase in the diameter of the reinforcing fibers. This is explained by the presence of the heterogeneous interface, which acts as a barrier to the propagation of shear bands and the atomic adjustment between Al and Ni stops the sliding and dislocations of the crystal planes.
In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Rang... more In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Range Order (MRO) in Mg-Al binary metallic glasses (MGs). The embedded atom method (EAM) has been adopted to accurately model the interatomic interactions. Various techniques such as radial distribution function (RDF), coordination number (CN) analyses and Gaussian fitting have been mobilized to comprehensively study the impact of cooling rate, composition and mechanical solicitations, on the structural properties at the MRO level. Our results reveal that the 1-atom connection mode is consistently dominant across all cooling rates. Moreover, as the cooling rate increases in the Mg 25 Al 75 binary MG, the abundance of the 4-atom and 2-atom connection modes increases, while the percentage of the 3-atom mode experiences a slight decrease. Furthermore, we investigate the influence of composition on the properties of Mg x Al 100-x alloys, demonstrating that the RDF peaks and connection modes are highly sensitive to variations in the Al concentration. Additionally, we explore the relationship between mechanical properties and connection modes during tensile deformation. The 3-atom connection mode exhibits superior hardness and stability, while the 4-atom and 2-atom connection modes offer increased flexibility. These significant findings enhance our understanding of MGs structural evolution, stability and deformation behavior. Ultimately, this knowledge facilitates the design and optimization of tailored MGs for advanced applications.
We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocompo... more We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocomposites (NCs) using molecular dynamics (MD) simulations within the framework of the Embedded Atom method (EAM). In terms of mechanical properties, metallic glass (MGs) are characterized by high performance, such as high yield strength and high strength, long-range atomic order is the main feature that links these mechanical properties to the structure of MGs. In the present work, the atomic structural characteristic of Al-MG is studied via several quantities such as radial distribution function (RDF), Voronoi tessellation analysis (VTA) and coordination number distribution (CN). Generally, the splitting of the second RDF peak during quenching confirmed the formation of Al-MG. The results of the application of a uniaxial tensile stress on the Al-MG samples and the NCs at 300 K with a strain rate of the order of 5. 10 8 s − 1 showed that the mechanical properties (Young's modulus, ultimate tensile strength, elastic limit, etc.) are improved by the reinforcement of the Al-MG matrix with fibers (cylinder) of crystalline nickel compared to that of-monatomic Al-MG. In general, it is observed that the ultimate tensile strength and Young's modulus increase with the increase in the diameter of the reinforcing fibers. This is explained by the presence of the heterogeneous interface, which acts as a barrier to the propagation of shear bands and the atomic adjustment between Al and Ni stops the sliding and dislocations of the crystal planes.
The aim of this study is to investigate how different pressure levels and annealing times affect ... more The aim of this study is to investigate how different pressure levels and annealing times affect the local atomic structure and mechanical properties of pure zirconium metallic glasses. Using molecular dynamics simulations with the embedded atom method, we explored how these changes influence the material's inherent characteristics. Analysis of the radial distribution function, coordination number, and Voronoi tessellation revealed a spectrum of structural arrangements in metallic glass formed across a pressure range of 0-70 GPa. Additionally, the glass transition temperature increased with increasing pressure, accompanied by reduced free volume. The annealing process, ranging from 0 to 5 ns on metallic glass synthesized under 0 GPa pressure, showed the coordination number's significance in achieving a glassy state. Regarding mechanical behavior, both elastic constants and moduli showed a progressive increase with rising pressure, while Young's modulus and hardness displayed enhanced values with longer annealing times.
In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metall... more In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metallic glass (MG) and three Mg-Al based nanoscale crystal/glass nanolaminates (NCGNLs) during crack propagation under tension loading are investigated using Molecular Dynamics (MD) simulations. The results observed in NCGNLs are compared with those related to pure MG to determine the effect of the NCGNLs on material strength and fracture toughness. The results show that the NCGNLs have a higher Young's modulus (E) and ultimate tensile strength (UTS) compared to pure MG. Which mean that the heterogeneous interphase between the crystalline layers and the amorphous pure glass behaves as the barriers behind the plastic deformation. Nano-patterning involving Aluminum (Al) and Magnesium (Mg) positively affects the fracture toughness of the material, while Mg 25 Al 75 / glass NCGNLs was found to be the most brittle and most prone to failure under tensile strain. The Al/glass NCGNLs is found to be the most ductile and able to withstand higher levels of strain before cracking. The simulations also reveal the deformation mechanisms at the atomic level, showing the nucleation/emission of dislocations types, twin boundary (TB), and stacking faults (SF) from the amorphous layer and their propagation to the Mg and Al crystal phases, respectively. These findings provide valuable insights into the mechanical properties of Mg-Al based nanolaminates and can inform the design of stronger and more durable materials.
In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Rang... more In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Range Order (MRO) in Mg-Al binary metallic glasses (MGs). The embedded atom method (EAM) has been adopted to accurately model the interatomic interactions. Various techniques such as radial distribution function (RDF), coordination number (CN) analyses and Gaussian fitting have been mobilized to comprehensively study the impact of cooling rate, composition and mechanical solicitations, on the structural properties at the MRO level. Our results reveal that the 1-atom connection mode is consistently dominant across all cooling rates. Moreover, as the cooling rate increases in the Mg 25 Al 75 binary MG, the abundance of the 4-atom and 2-atom connection modes increases, while the percentage of the 3-atom mode experiences a slight decrease. Furthermore, we investigate the influence of composition on the properties of Mg x Al 100-x alloys, demonstrating that the RDF peaks and connection modes are highly sensitive to variations in the Al concentration. Additionally, we explore the relationship between mechanical properties and connection modes during tensile deformation. The 3-atom connection mode exhibits superior hardness and stability, while the 4-atom and 2-atom connection modes offer increased flexibility. These significant findings enhance our understanding of MGs structural evolution, stability and deformation behavior. Ultimately, this knowledge facilitates the design and optimization of tailored MGs for advanced applications.
The search for advanced materials has been the main preoccupation of materials scientists for the... more The search for advanced materials has been the main preoccupation of materials scientists for the past years. Binary Re-W metallic glasses (MGs) are very promising candidates for many applications requiring good mechanical proprieties. Molecular Dynamics (MD) simulations with the embedded atom method (EAM) potential have been devoted to investigate the behavior of these materials by exploring their local atomic structure by means of various techniques such as the radial distribution function (RDF), the Voronoi Tessellation Analysis (VTA) and the coordination number (CN). The results showed a splitting in the second peak of RDFs indicating the formation of Re-W metallic glasses. The VTA method showed that the <0,1,10,2> icosahedral Voronoi cluster is the major short-range unit in Re-W MGs. The icosahedral-like cluster abundance is proposed as a measure of vitrification which has been shown to be promoted by the increase of W content. The coordination number analysis showed the existence of transition from low-to high-coordinated atoms occurring at the glass transition temperature. These simulated structural properties were used mainly to study the glass transition temperature T g using different methods, including the Wendt-Abraham method which is considered as a reference method. Essentially, we suggest the intersection between low-and high-coordinated atom populations to be a measure of T g .
Journal of Alloys and Compounds , 2021
Molecular dynamics (MD) simulations based on the embedded atomic method (EAM) are used to study t... more Molecular dynamics (MD) simulations based on the embedded atomic method (EAM) are used to study the annealing effect on elastic and structural behavior for different cooling rates of binary Mg Al 25 75 metallic glasses (MGs). Firstly, we examine the cooling rates effect (K s 5 10 / 11 × , K s 10 / , 12 K s 5 10 / 12 < > < > clusters and the degree of the five-fold symmetry increase as a function of the increase of annealing time.
Using molecular dynamics simulations with the embedded atomic method (EAM) to describe interatomi... more Using molecular dynamics simulations with the embedded atomic method (EAM) to describe interatomic interactions , structural and mechanical properties of Mg-Al metallic glasses (MG) have been investigated for different compositions. The atomic structure is characterized using various techniques such as the Radial Distribution Function (RDF), the Voronoi Tessellation Analysis (VTA) and coordination number (CN) distribution. The results confirmed that the Mg-Al glass formation is accompanied by a splitting of the RDF second peak upon cooling process. The glass transition temperature is determined using different method involving a new suggested way consisting of the cross-over between low and high coordination numbers curves during cooling process. This last technique gives approximate results that converge to those given by classical methods. On the other hand, we applied a strain-rate of 10 10 s −1 at 300 K and showed that with the increase of Al composition, the maximal stress incr...
Materials today communications, Jul 1, 2024
In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metall... more In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metallic glass (MG) and three Mg-Al based nanoscale crystal/glass nanolaminates (NCGNLs) during crack propagation under tension loading are investigated using Molecular Dynamics (MD) simulations. The results observed in NCGNLs are compared with those related to pure MG to determine the effect of the NCGNLs on material strength and fracture toughness. The results show that the NCGNLs have a higher Young's modulus (E) and ultimate tensile strength (UTS) compared to pure MG. Which mean that the heterogeneous interphase between the crystalline layers and the amorphous pure glass behaves as the barriers behind the plastic deformation. Nano-patterning involving Aluminum (Al) and Magnesium (Mg) positively affects the fracture toughness of the material, while Mg 25 Al 75 / glass NCGNLs was found to be the most brittle and most prone to failure under tensile strain. The Al/glass NCGNLs is found to be the most ductile and able to withstand higher levels of strain before cracking. The simulations also reveal the deformation mechanisms at the atomic level, showing the nucleation/emission of dislocations types, twin boundary (TB), and stacking faults (SF) from the amorphous layer and their propagation to the Mg and Al crystal phases, respectively. These findings provide valuable insights into the mechanical properties of Mg-Al based nanolaminates and can inform the design of stronger and more durable materials.
We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocompo... more We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocomposites (NCs) using molecular dynamics (MD) simulations within the framework of the Embedded Atom method (EAM). In terms of mechanical properties, metallic glass (MGs) are characterized by high performance, such as high yield strength and high strength, long-range atomic order is the main feature that links these mechanical properties to the structure of MGs. In the present work, the atomic structural characteristic of Al-MG is studied via several quantities such as radial distribution function (RDF), Voronoi tessellation analysis (VTA) and coordination number distribution (CN). Generally, the splitting of the second RDF peak during quenching confirmed the formation of Al-MG. The results of the application of a uniaxial tensile stress on the Al-MG samples and the NCs at 300 K with a strain rate of the order of 5. 10 8 s − 1 showed that the mechanical properties (Young's modulus, ultimate tensile strength, elastic limit, etc.) are improved by the reinforcement of the Al-MG matrix with fibers (cylinder) of crystalline nickel compared to that of-monatomic Al-MG. In general, it is observed that the ultimate tensile strength and Young's modulus increase with the increase in the diameter of the reinforcing fibers. This is explained by the presence of the heterogeneous interface, which acts as a barrier to the propagation of shear bands and the atomic adjustment between Al and Ni stops the sliding and dislocations of the crystal planes.
In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Rang... more In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Range Order (MRO) in Mg-Al binary metallic glasses (MGs). The embedded atom method (EAM) has been adopted to accurately model the interatomic interactions. Various techniques such as radial distribution function (RDF), coordination number (CN) analyses and Gaussian fitting have been mobilized to comprehensively study the impact of cooling rate, composition and mechanical solicitations, on the structural properties at the MRO level. Our results reveal that the 1-atom connection mode is consistently dominant across all cooling rates. Moreover, as the cooling rate increases in the Mg 25 Al 75 binary MG, the abundance of the 4-atom and 2-atom connection modes increases, while the percentage of the 3-atom mode experiences a slight decrease. Furthermore, we investigate the influence of composition on the properties of Mg x Al 100-x alloys, demonstrating that the RDF peaks and connection modes are highly sensitive to variations in the Al concentration. Additionally, we explore the relationship between mechanical properties and connection modes during tensile deformation. The 3-atom connection mode exhibits superior hardness and stability, while the 4-atom and 2-atom connection modes offer increased flexibility. These significant findings enhance our understanding of MGs structural evolution, stability and deformation behavior. Ultimately, this knowledge facilitates the design and optimization of tailored MGs for advanced applications.
We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocompo... more We study the mechanical behavior of Aluminum metallic glass (Al-MG) and Al-based matrix nanocomposites (NCs) using molecular dynamics (MD) simulations within the framework of the Embedded Atom method (EAM). In terms of mechanical properties, metallic glass (MGs) are characterized by high performance, such as high yield strength and high strength, long-range atomic order is the main feature that links these mechanical properties to the structure of MGs. In the present work, the atomic structural characteristic of Al-MG is studied via several quantities such as radial distribution function (RDF), Voronoi tessellation analysis (VTA) and coordination number distribution (CN). Generally, the splitting of the second RDF peak during quenching confirmed the formation of Al-MG. The results of the application of a uniaxial tensile stress on the Al-MG samples and the NCs at 300 K with a strain rate of the order of 5. 10 8 s − 1 showed that the mechanical properties (Young's modulus, ultimate tensile strength, elastic limit, etc.) are improved by the reinforcement of the Al-MG matrix with fibers (cylinder) of crystalline nickel compared to that of-monatomic Al-MG. In general, it is observed that the ultimate tensile strength and Young's modulus increase with the increase in the diameter of the reinforcing fibers. This is explained by the presence of the heterogeneous interface, which acts as a barrier to the propagation of shear bands and the atomic adjustment between Al and Ni stops the sliding and dislocations of the crystal planes.
The aim of this study is to investigate how different pressure levels and annealing times affect ... more The aim of this study is to investigate how different pressure levels and annealing times affect the local atomic structure and mechanical properties of pure zirconium metallic glasses. Using molecular dynamics simulations with the embedded atom method, we explored how these changes influence the material's inherent characteristics. Analysis of the radial distribution function, coordination number, and Voronoi tessellation revealed a spectrum of structural arrangements in metallic glass formed across a pressure range of 0-70 GPa. Additionally, the glass transition temperature increased with increasing pressure, accompanied by reduced free volume. The annealing process, ranging from 0 to 5 ns on metallic glass synthesized under 0 GPa pressure, showed the coordination number's significance in achieving a glassy state. Regarding mechanical behavior, both elastic constants and moduli showed a progressive increase with rising pressure, while Young's modulus and hardness displayed enhanced values with longer annealing times.
In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metall... more In this paper, the mechanical properties and plastic deformation mechanisms of Mg 25 Al 75 metallic glass (MG) and three Mg-Al based nanoscale crystal/glass nanolaminates (NCGNLs) during crack propagation under tension loading are investigated using Molecular Dynamics (MD) simulations. The results observed in NCGNLs are compared with those related to pure MG to determine the effect of the NCGNLs on material strength and fracture toughness. The results show that the NCGNLs have a higher Young's modulus (E) and ultimate tensile strength (UTS) compared to pure MG. Which mean that the heterogeneous interphase between the crystalline layers and the amorphous pure glass behaves as the barriers behind the plastic deformation. Nano-patterning involving Aluminum (Al) and Magnesium (Mg) positively affects the fracture toughness of the material, while Mg 25 Al 75 / glass NCGNLs was found to be the most brittle and most prone to failure under tensile strain. The Al/glass NCGNLs is found to be the most ductile and able to withstand higher levels of strain before cracking. The simulations also reveal the deformation mechanisms at the atomic level, showing the nucleation/emission of dislocations types, twin boundary (TB), and stacking faults (SF) from the amorphous layer and their propagation to the Mg and Al crystal phases, respectively. These findings provide valuable insights into the mechanical properties of Mg-Al based nanolaminates and can inform the design of stronger and more durable materials.
In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Rang... more In this work, we used molecular dynamics (MD) simulations in order to investigate the Medium-Range Order (MRO) in Mg-Al binary metallic glasses (MGs). The embedded atom method (EAM) has been adopted to accurately model the interatomic interactions. Various techniques such as radial distribution function (RDF), coordination number (CN) analyses and Gaussian fitting have been mobilized to comprehensively study the impact of cooling rate, composition and mechanical solicitations, on the structural properties at the MRO level. Our results reveal that the 1-atom connection mode is consistently dominant across all cooling rates. Moreover, as the cooling rate increases in the Mg 25 Al 75 binary MG, the abundance of the 4-atom and 2-atom connection modes increases, while the percentage of the 3-atom mode experiences a slight decrease. Furthermore, we investigate the influence of composition on the properties of Mg x Al 100-x alloys, demonstrating that the RDF peaks and connection modes are highly sensitive to variations in the Al concentration. Additionally, we explore the relationship between mechanical properties and connection modes during tensile deformation. The 3-atom connection mode exhibits superior hardness and stability, while the 4-atom and 2-atom connection modes offer increased flexibility. These significant findings enhance our understanding of MGs structural evolution, stability and deformation behavior. Ultimately, this knowledge facilitates the design and optimization of tailored MGs for advanced applications.
The search for advanced materials has been the main preoccupation of materials scientists for the... more The search for advanced materials has been the main preoccupation of materials scientists for the past years. Binary Re-W metallic glasses (MGs) are very promising candidates for many applications requiring good mechanical proprieties. Molecular Dynamics (MD) simulations with the embedded atom method (EAM) potential have been devoted to investigate the behavior of these materials by exploring their local atomic structure by means of various techniques such as the radial distribution function (RDF), the Voronoi Tessellation Analysis (VTA) and the coordination number (CN). The results showed a splitting in the second peak of RDFs indicating the formation of Re-W metallic glasses. The VTA method showed that the <0,1,10,2> icosahedral Voronoi cluster is the major short-range unit in Re-W MGs. The icosahedral-like cluster abundance is proposed as a measure of vitrification which has been shown to be promoted by the increase of W content. The coordination number analysis showed the existence of transition from low-to high-coordinated atoms occurring at the glass transition temperature. These simulated structural properties were used mainly to study the glass transition temperature T g using different methods, including the Wendt-Abraham method which is considered as a reference method. Essentially, we suggest the intersection between low-and high-coordinated atom populations to be a measure of T g .
Journal of Alloys and Compounds , 2021
Molecular dynamics (MD) simulations based on the embedded atomic method (EAM) are used to study t... more Molecular dynamics (MD) simulations based on the embedded atomic method (EAM) are used to study the annealing effect on elastic and structural behavior for different cooling rates of binary Mg Al 25 75 metallic glasses (MGs). Firstly, we examine the cooling rates effect (K s 5 10 / 11 × , K s 10 / , 12 K s 5 10 / 12 < > < > clusters and the degree of the five-fold symmetry increase as a function of the increase of annealing time.
Using molecular dynamics simulations with the embedded atomic method (EAM) to describe interatomi... more Using molecular dynamics simulations with the embedded atomic method (EAM) to describe interatomic interactions , structural and mechanical properties of Mg-Al metallic glasses (MG) have been investigated for different compositions. The atomic structure is characterized using various techniques such as the Radial Distribution Function (RDF), the Voronoi Tessellation Analysis (VTA) and coordination number (CN) distribution. The results confirmed that the Mg-Al glass formation is accompanied by a splitting of the RDF second peak upon cooling process. The glass transition temperature is determined using different method involving a new suggested way consisting of the cross-over between low and high coordination numbers curves during cooling process. This last technique gives approximate results that converge to those given by classical methods. On the other hand, we applied a strain-rate of 10 10 s −1 at 300 K and showed that with the increase of Al composition, the maximal stress incr...