Amdulla Mekhrabov - Academia.edu (original) (raw)

Papers by Amdulla Mekhrabov

Research paper thumbnail of Microstructural evolution and room-temperature mechanical properties of as-cast and heat-treated Fe50Al50−nNbn alloys (n=1, 3, 5, 7, and 9at%)

Materials Science and Engineering: A, 2016

Research paper thumbnail of High-Temperature X-ray Diffraction Studies of Lattice Dynamics in Ni 3 (Fe,Nb) Ordered Alloys

Acta Physica Polonica A, 1994

Research paper thumbnail of Impurity effect of Me=Cr, Nb or Mn third component atoms on hyperfine interactions in ordered Ni3Fe alloy

Hyperfine Interactions, 1990

Research paper thumbnail of Theoretical prediction of bulk glass forming ability (BGFA) of Ti�Cu based multicomponent alloys

Journal of Non Crystalline Solids, Mar 1, 2009

Research paper thumbnail of Microstructural and magnetic characterization of iron precipitation in Ni–Fe–Al alloys

Materials Characterization, Jun 1, 2011

The influence of annealing on the microstructural evolution and magnetic properties of Ni50FexAl5... more The influence of annealing on the microstructural evolution and magnetic properties of Ni50FexAl50 − x alloys for x = 20, 25, and 30 has been investigated. Solidification microstructures of as-cast alloys reveal coarse grains of a single B2 type β-phase and typical off eutectic microstructure consisting of proeutectic B2 type β dendrites and interdendritic eutectic for x = 20 and x > 20 at.% Fe respectively. However, annealing at 1073 K results in the formation of FCC γ-phase particles along the grain boundaries as well as grain interior in x = 20 at.% Fe alloy. The volume fraction of interdentritic eutectic regions tend to decrease and their morphologies start to degenerate by forming FCC γ-phase for x > 20 at.% Fe alloys with increasing annealing temperatures. Increasing Fe content of alloys induce an enhancement in magnetization and a rise in the Curie transition temperature (TC). Temperature scan magnetic measurements and transmission electron microscopy reveal that a transient rise in the magnetization at temperatures well above the TC of the alloys would be attributed to the precipitation of a nano-scale ferromagnetic BCC α-Fe phase. Retained magnetization above the Curie transition temperature of alloy matrix, together with enhanced room temperature saturation magnetization of alloys annealed at favorable temperatures support the presence of ferromagnetic precipitates. These nano-scale precipitates are shown to induce significant precipitation hardening of the β-phase in conjunction with enhanced room temperature saturation magnetization in particular when an annealing temperature of 673 K is used.► Evolution of microstructure and magnetic properties with varying Fe content. ► Transient rise in magnetization via the formation of ferromagnetic phase. ► Enhancements in saturation magnetization owing to precipitated ferromagnetic phase. ► Nanoscale precipitation of ferromagnetic BCC α-Fe confirmed by TEM. ► Hardness of the β-phase correlates with room temperature saturation magnetization.

Research paper thumbnail of The Influence of Vacancies on Radiation-Enhanced Phase Transition in Fe-Ni-Cr Alloys

Materials Science Forum, 1987

Research paper thumbnail of The effect of substitutional impurities on the evolution of Fe?Al diffusion layer

Research paper thumbnail of A generalized polytetrahedral cluster approach to partial coordination numbers in binary metallic glasses

Http Dx Doi Org 10 1080 14786435 2011 558031, Apr 5, 2011

ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coor... more ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coordinated local structure and related short-range order in metallic glasses. By defining a polytetrahedral aggregation for solute–solvent type atomic clusters, which retains cluster sphericity, high solute–solvent and solvent–solvent CNs, a preliminary model is developed to estimate the CN of a solute atom within a non-isolated cluster embedded in the glassy environment. Employing the result, a generalized quasi-hard sphere model is constructed by defining intra- and inter-cluster correlations, which can yield significantly close values to experimentally derived partial CNs in a great many metallic glass systems, such as Fe–B, Ni–B, Ni–P, Co–P, Pd–Si, Al–Y, Co–Zr, Co–Ti, Ni–Ti, Zr–Ni, Zr–Pd, Zr–Pt and Cu–Zr. The approach allows evaluation of a complete set of partial CNs in a given binary system as a function of atomic radii and composition.

Research paper thumbnail of The Effect of Alloying Additions on the Interfacial Interactions at the Fe-Al Interface During Coating

Research paper thumbnail of Magnetostriction in laves phase compounds RE1−xPrxFe2 (RE = Ce, Sm and Y) and their easy axes of magnetization

Research paper thumbnail of Effect of Ternary Alloying Elements Addition Mehmet YILDIRIM 2012METTRANSA Paper

Research paper thumbnail of The role of Si addition on the interfacial interaction in FeAl diffusion layer

Scripta Metallurgica et Materialia, 1994

The formation and growth characteristics of the diffusion layers formed at the aluminum-steel int... more The formation and growth characteristics of the diffusion layers formed at the aluminum-steel interface depend on several factors, such as the crystal structure, the range of solid solubility, the magnitude and sign of interatomic interaction potentials between the atoms of substrate and coating elements, and also their interdiffusion coefficient. The interfacial interactions either increase or decrease depending on the nature

Research paper thumbnail of Microstructural Examination of Mn Alloyed Fe-Al Based Intermetallics

MORRIS:INTERMETALLICS O-BK, 2000

ABSTRACT In this present study, in order to improve the mechanical properties of the Fe-Al-Mn all... more ABSTRACT In this present study, in order to improve the mechanical properties of the Fe-Al-Mn alloys that may be considered as the substitutes for conventional stainless steels, the melt suction process was employed to ensure the formation of refined, rapidly solidified microstructure. The effects of ternary alloying additions on the solidification structures and ordering characteristics of Fe-Al alloys were examined. The microstructural observation and structural analysis performed on the specimens alloyed with Mn suggested that phase decomposition occurs during rapid solidification processing which leads to the formation of κ-phase type carbides distributed within disordered austenitic matrix. Lattice parameter of austenitic Fe-Al-Mn-C alloys is a function of the composition and increases with increasing Mn content.

Research paper thumbnail of Electronic Theory of Atomic Short-Range Order for Ternary Alloys Using the Pseudopotential Approximation and Its Comparison with Experiments

physica status solidi (b), 1984

... In the present paper for the calculation of the partial ordering energies and SRO parameters ... more ... In the present paper for the calculation of the partial ordering energies and SRO parameters according to (1) to (11) programmes for computer in Fortran were compos-ed. Direct calculations were made for ... [2] A. A. KATSNELSON, V. M. SILONOV, and FARID A. KHWAJA, phys. ...

Research paper thumbnail of The Effect of a Third Component Impurity C on the Heat Capacity of A3B-Type Ordered Alloys

physica status solidi (b), 1989

ABSTRACT For the first time theoretical (in terms of the classical theory of ordering) and experi... more ABSTRACT For the first time theoretical (in terms of the classical theory of ordering) and experimental (with the adiabatic calorimeter method) investigations are made of the effect of a third component impurity C on the heat capacity of A3B-type ordered alloys with FCC structure. The effect of the impurities Mn, Cr, Mo, or W on the heat capacity of Ni3Fe alloys is analysed as an example. The comparison of the theoretical results with the experimental data shows good qualitative agreement.[Russian Text Ignored].

Research paper thumbnail of Transition-metal electron states in imperfect Ga2S3 crystals

Physica Status Solidi (a), 1988

... 2 3: 2 3 compounds /9, lo/. Resonance techniques and, in particular, electron paramagnetic re... more ... 2 3: 2 3 compounds /9, lo/. Resonance techniques and, in particular, electron paramagnetic resonance (EPR) and 7-resonance (GR) are the most informative ones for the interpretation of the impurity character in defect semiconductors. ... 1) 13 Krylov Str., SU-370073 Baku, USSR. ...

Research paper thumbnail of A generalized polytetrahedral cluster approach to partial coordination numbers in binary metallic glasses

Philosophical Magazine, 2011

ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coor... more ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coordinated local structure and related short-range order in metallic glasses. By defining a polytetrahedral aggregation for solute–solvent type atomic clusters, which retains cluster sphericity, high solute–solvent and solvent–solvent CNs, a preliminary model is developed to estimate the CN of a solute atom within a non-isolated cluster embedded in the glassy environment. Employing the result, a generalized quasi-hard sphere model is constructed by defining intra- and inter-cluster correlations, which can yield significantly close values to experimentally derived partial CNs in a great many metallic glass systems, such as Fe–B, Ni–B, Ni–P, Co–P, Pd–Si, Al–Y, Co–Zr, Co–Ti, Ni–Ti, Zr–Ni, Zr–Pd, Zr–Pt and Cu–Zr. The approach allows evaluation of a complete set of partial CNs in a given binary system as a function of atomic radii and composition.

Research paper thumbnail of Modelling and Monte Carlo simulation of the atomic ordering processes in Ni 3 Al intermetallics

Modelling and Simulation in Materials Science and Engineering, 2007

ABSTRACT The evolution of atomic ordering processes in Ni3Al has been modelled by a Monte Carlo (... more ABSTRACT The evolution of atomic ordering processes in Ni3Al has been modelled by a Monte Carlo (MC) simulation method combined with the electronic theory of alloys in pseudopotential approximation. The magnitudes of atomic ordering energies of atomic pairs in the Ni3Al system have been calculated by means of electronic theory in pseudopotential approximation up to the 4th coordination spheres and subsequently used as input data for MC simulation for more detailed analysis for the first time. The Bragg–Williams long-range order (LRO) and Cowley–Warren short-range order (SRO) parameters have been calculated from the equilibrium configurations attained at the end of the MC simulation for each predefined temperature and Al concentration levels which reveal the evolution of the system from the L12 → disordered state as the temperature increases. The values of the LRO and SRO parameters at temperatures below 800 °C justify the existence of L12-type ordered Ni3Al alloys for all concentration levels whereas at temperatures above 850 °C, the values of the LRO parameter implies the presence of a disordered solid solution of Ni3Al alloys. However, a higher degree of the SRO order parameter above the predicted order–disorder transition temperature is preserved up to the melting point of Ni3Al intermetallics. The composition dependence of the LRO and SRO parameters agrees well with the experimental results.

Research paper thumbnail of Solidification Microstructures and Carbides Morphology in Rapidly Solidified Fe-Al-Cr-C Alloys

Metals and Materials International, 2008

Research paper thumbnail of Microstructural Investigation and Phase Relationships of Fe-Al-Hf Alloys

Metallurgical and Materials Transactions A, 2014

Research paper thumbnail of Microstructural evolution and room-temperature mechanical properties of as-cast and heat-treated Fe50Al50−nNbn alloys (n=1, 3, 5, 7, and 9at%)

Materials Science and Engineering: A, 2016

Research paper thumbnail of High-Temperature X-ray Diffraction Studies of Lattice Dynamics in Ni 3 (Fe,Nb) Ordered Alloys

Acta Physica Polonica A, 1994

Research paper thumbnail of Impurity effect of Me=Cr, Nb or Mn third component atoms on hyperfine interactions in ordered Ni3Fe alloy

Hyperfine Interactions, 1990

Research paper thumbnail of Theoretical prediction of bulk glass forming ability (BGFA) of Ti�Cu based multicomponent alloys

Journal of Non Crystalline Solids, Mar 1, 2009

Research paper thumbnail of Microstructural and magnetic characterization of iron precipitation in Ni–Fe–Al alloys

Materials Characterization, Jun 1, 2011

The influence of annealing on the microstructural evolution and magnetic properties of Ni50FexAl5... more The influence of annealing on the microstructural evolution and magnetic properties of Ni50FexAl50 − x alloys for x = 20, 25, and 30 has been investigated. Solidification microstructures of as-cast alloys reveal coarse grains of a single B2 type β-phase and typical off eutectic microstructure consisting of proeutectic B2 type β dendrites and interdendritic eutectic for x = 20 and x > 20 at.% Fe respectively. However, annealing at 1073 K results in the formation of FCC γ-phase particles along the grain boundaries as well as grain interior in x = 20 at.% Fe alloy. The volume fraction of interdentritic eutectic regions tend to decrease and their morphologies start to degenerate by forming FCC γ-phase for x > 20 at.% Fe alloys with increasing annealing temperatures. Increasing Fe content of alloys induce an enhancement in magnetization and a rise in the Curie transition temperature (TC). Temperature scan magnetic measurements and transmission electron microscopy reveal that a transient rise in the magnetization at temperatures well above the TC of the alloys would be attributed to the precipitation of a nano-scale ferromagnetic BCC α-Fe phase. Retained magnetization above the Curie transition temperature of alloy matrix, together with enhanced room temperature saturation magnetization of alloys annealed at favorable temperatures support the presence of ferromagnetic precipitates. These nano-scale precipitates are shown to induce significant precipitation hardening of the β-phase in conjunction with enhanced room temperature saturation magnetization in particular when an annealing temperature of 673 K is used.► Evolution of microstructure and magnetic properties with varying Fe content. ► Transient rise in magnetization via the formation of ferromagnetic phase. ► Enhancements in saturation magnetization owing to precipitated ferromagnetic phase. ► Nanoscale precipitation of ferromagnetic BCC α-Fe confirmed by TEM. ► Hardness of the β-phase correlates with room temperature saturation magnetization.

Research paper thumbnail of The Influence of Vacancies on Radiation-Enhanced Phase Transition in Fe-Ni-Cr Alloys

Materials Science Forum, 1987

Research paper thumbnail of The effect of substitutional impurities on the evolution of Fe?Al diffusion layer

Research paper thumbnail of A generalized polytetrahedral cluster approach to partial coordination numbers in binary metallic glasses

Http Dx Doi Org 10 1080 14786435 2011 558031, Apr 5, 2011

ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coor... more ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coordinated local structure and related short-range order in metallic glasses. By defining a polytetrahedral aggregation for solute–solvent type atomic clusters, which retains cluster sphericity, high solute–solvent and solvent–solvent CNs, a preliminary model is developed to estimate the CN of a solute atom within a non-isolated cluster embedded in the glassy environment. Employing the result, a generalized quasi-hard sphere model is constructed by defining intra- and inter-cluster correlations, which can yield significantly close values to experimentally derived partial CNs in a great many metallic glass systems, such as Fe–B, Ni–B, Ni–P, Co–P, Pd–Si, Al–Y, Co–Zr, Co–Ti, Ni–Ti, Zr–Ni, Zr–Pd, Zr–Pt and Cu–Zr. The approach allows evaluation of a complete set of partial CNs in a given binary system as a function of atomic radii and composition.

Research paper thumbnail of The Effect of Alloying Additions on the Interfacial Interactions at the Fe-Al Interface During Coating

Research paper thumbnail of Magnetostriction in laves phase compounds RE1−xPrxFe2 (RE = Ce, Sm and Y) and their easy axes of magnetization

Research paper thumbnail of Effect of Ternary Alloying Elements Addition Mehmet YILDIRIM 2012METTRANSA Paper

Research paper thumbnail of The role of Si addition on the interfacial interaction in FeAl diffusion layer

Scripta Metallurgica et Materialia, 1994

The formation and growth characteristics of the diffusion layers formed at the aluminum-steel int... more The formation and growth characteristics of the diffusion layers formed at the aluminum-steel interface depend on several factors, such as the crystal structure, the range of solid solubility, the magnitude and sign of interatomic interaction potentials between the atoms of substrate and coating elements, and also their interdiffusion coefficient. The interfacial interactions either increase or decrease depending on the nature

Research paper thumbnail of Microstructural Examination of Mn Alloyed Fe-Al Based Intermetallics

MORRIS:INTERMETALLICS O-BK, 2000

ABSTRACT In this present study, in order to improve the mechanical properties of the Fe-Al-Mn all... more ABSTRACT In this present study, in order to improve the mechanical properties of the Fe-Al-Mn alloys that may be considered as the substitutes for conventional stainless steels, the melt suction process was employed to ensure the formation of refined, rapidly solidified microstructure. The effects of ternary alloying additions on the solidification structures and ordering characteristics of Fe-Al alloys were examined. The microstructural observation and structural analysis performed on the specimens alloyed with Mn suggested that phase decomposition occurs during rapid solidification processing which leads to the formation of κ-phase type carbides distributed within disordered austenitic matrix. Lattice parameter of austenitic Fe-Al-Mn-C alloys is a function of the composition and increases with increasing Mn content.

Research paper thumbnail of Electronic Theory of Atomic Short-Range Order for Ternary Alloys Using the Pseudopotential Approximation and Its Comparison with Experiments

physica status solidi (b), 1984

... In the present paper for the calculation of the partial ordering energies and SRO parameters ... more ... In the present paper for the calculation of the partial ordering energies and SRO parameters according to (1) to (11) programmes for computer in Fortran were compos-ed. Direct calculations were made for ... [2] A. A. KATSNELSON, V. M. SILONOV, and FARID A. KHWAJA, phys. ...

Research paper thumbnail of The Effect of a Third Component Impurity C on the Heat Capacity of A3B-Type Ordered Alloys

physica status solidi (b), 1989

ABSTRACT For the first time theoretical (in terms of the classical theory of ordering) and experi... more ABSTRACT For the first time theoretical (in terms of the classical theory of ordering) and experimental (with the adiabatic calorimeter method) investigations are made of the effect of a third component impurity C on the heat capacity of A3B-type ordered alloys with FCC structure. The effect of the impurities Mn, Cr, Mo, or W on the heat capacity of Ni3Fe alloys is analysed as an example. The comparison of the theoretical results with the experimental data shows good qualitative agreement.[Russian Text Ignored].

Research paper thumbnail of Transition-metal electron states in imperfect Ga2S3 crystals

Physica Status Solidi (a), 1988

... 2 3: 2 3 compounds /9, lo/. Resonance techniques and, in particular, electron paramagnetic re... more ... 2 3: 2 3 compounds /9, lo/. Resonance techniques and, in particular, electron paramagnetic resonance (EPR) and 7-resonance (GR) are the most informative ones for the interpretation of the impurity character in defect semiconductors. ... 1) 13 Krylov Str., SU-370073 Baku, USSR. ...

Research paper thumbnail of A generalized polytetrahedral cluster approach to partial coordination numbers in binary metallic glasses

Philosophical Magazine, 2011

ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coor... more ABSTRACT Partial coordination numbers (CNs) play a substantial role in description of hetero-coordinated local structure and related short-range order in metallic glasses. By defining a polytetrahedral aggregation for solute–solvent type atomic clusters, which retains cluster sphericity, high solute–solvent and solvent–solvent CNs, a preliminary model is developed to estimate the CN of a solute atom within a non-isolated cluster embedded in the glassy environment. Employing the result, a generalized quasi-hard sphere model is constructed by defining intra- and inter-cluster correlations, which can yield significantly close values to experimentally derived partial CNs in a great many metallic glass systems, such as Fe–B, Ni–B, Ni–P, Co–P, Pd–Si, Al–Y, Co–Zr, Co–Ti, Ni–Ti, Zr–Ni, Zr–Pd, Zr–Pt and Cu–Zr. The approach allows evaluation of a complete set of partial CNs in a given binary system as a function of atomic radii and composition.

Research paper thumbnail of Modelling and Monte Carlo simulation of the atomic ordering processes in Ni 3 Al intermetallics

Modelling and Simulation in Materials Science and Engineering, 2007

ABSTRACT The evolution of atomic ordering processes in Ni3Al has been modelled by a Monte Carlo (... more ABSTRACT The evolution of atomic ordering processes in Ni3Al has been modelled by a Monte Carlo (MC) simulation method combined with the electronic theory of alloys in pseudopotential approximation. The magnitudes of atomic ordering energies of atomic pairs in the Ni3Al system have been calculated by means of electronic theory in pseudopotential approximation up to the 4th coordination spheres and subsequently used as input data for MC simulation for more detailed analysis for the first time. The Bragg–Williams long-range order (LRO) and Cowley–Warren short-range order (SRO) parameters have been calculated from the equilibrium configurations attained at the end of the MC simulation for each predefined temperature and Al concentration levels which reveal the evolution of the system from the L12 → disordered state as the temperature increases. The values of the LRO and SRO parameters at temperatures below 800 °C justify the existence of L12-type ordered Ni3Al alloys for all concentration levels whereas at temperatures above 850 °C, the values of the LRO parameter implies the presence of a disordered solid solution of Ni3Al alloys. However, a higher degree of the SRO order parameter above the predicted order–disorder transition temperature is preserved up to the melting point of Ni3Al intermetallics. The composition dependence of the LRO and SRO parameters agrees well with the experimental results.

Research paper thumbnail of Solidification Microstructures and Carbides Morphology in Rapidly Solidified Fe-Al-Cr-C Alloys

Metals and Materials International, 2008

Research paper thumbnail of Microstructural Investigation and Phase Relationships of Fe-Al-Hf Alloys

Metallurgical and Materials Transactions A, 2014