Seung Zeon Han Han - Academia.edu (original) (raw)
Papers by Seung Zeon Han Han
ACS Applied Electronic Materials
Bulletin of the American Physical Society, 2019
Acta Materialia, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Philosophical Magazine Letters, 2020
The effect of deformation before aging on discontinuous precipitation in Cu-4.75wt%Ni-1.13wt%Si a... more The effect of deformation before aging on discontinuous precipitation in Cu-4.75wt%Ni-1.13wt%Si and Cu-6wt%Ni-1.42wt%Si alloys after solution treatment was investigated. Two kinds of deformation, one under and the other over the uniform deformation limit were implemented after solution treatment. With increasing deformation strain in both alloys, the discontinuous precipitation is accelerated and the aging time for a fully covered region by discontinuous precipitation is shortened. However, the Cu-6wt%Ni-1.42wt%Si alloy deformed under the uniform deformation limits showed an enhanced discontinuous precipitation compared to that for the alloy deformed over the uniform deformation limit. The deformation defects including dislocations and shear bands play the role of encouraging discontinuous precipitation. The shear bands formed during prior deformation beyond the necking point could provide sites for discontinuous precipitation initiation in the early stages of annealing However, shear bands tend to hinder the advance of discontinuous precipitation with further aging in the Cu-Ni-Si alloy with a high content of Ni and Si.
Progress in Materials Science, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The Proceedings of the Materials and processing conference, 2018
Journal of Alloys and Compounds, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Korean Journal of Metals and Materials, 2019
Cu-Ti alloys were strengthened by Cu 4 Ti intermetallic compound precipitation in a Cu matrix dur... more Cu-Ti alloys were strengthened by Cu 4 Ti intermetallic compound precipitation in a Cu matrix during aging. The Cu-3.5 wt% Ti(Cu-4.6 at% Ti) alloys without deformation and with uniform and nonuniform deformation were aged at 450 o C for various times after solution treatment at 885 o C. The uniformly and non-uniformly deformed alloys show slip and shear band formation in the matrix, respectively. The deformation bands, slip or shear bands, were still maintained even after 12 hours of aging at 450 o C. The conductivity of all the specimens continuously increased, but the hardness reached the peak value and then decreased during aging. The hardness and conductivity of the specimen with shear bands had a higher value than the specimens without deformation and with slip bands. Additionally, the time to reach peak hardness of the specimen with shear bands was shortened to 30 minutes compared to 720 and 1440 minutes for specimens with slip bands and without deformation bands, respectively. The highest combination value of conductivity and hardness, 16.8% IACS and 302 Hv, was obtained in the specimen with shear bands after aging for 360 minutes.
The Proceedings of the Materials and Mechanics Conference, 2008
Egual channel angula 厂 pre ． ∬η 9， Cop ρ er ． Shea广 わ α ηみ ， Sttrface c 厂 ack
Materials Science and Engineering: A, 2017
A technique of fabricating ultrafine grained Fe-based shape memory alloys with high strength via ... more A technique of fabricating ultrafine grained Fe-based shape memory alloys with high strength via differential speed rolling with high speed ratios of 2-3.8 and subsequent annealing was proposed. The processed alloy exhibited a markedly higher recovery stress compared to the same alloy with a coarse grain size.
Journal of the Society of Materials Science, Japan, 2004
International Journal of Fatigue, 2016
Abstract The formation mechanism of inclined fatigue-cracks in ultrafine-grained Cu processed by ... more Abstract The formation mechanism of inclined fatigue-cracks in ultrafine-grained Cu processed by equal channel angular pressing was studied by using a partially notched specimen in which a fatal natural crack was introduced, to a specific site of the smooth surface was feasible regardless of microstructural inhomogeneity caused by the processing. The crack growth direction depended on the location along the circumferential direction of the round bar specimen and on the applied stress amplitudes. The role of the microstructure and deformation mode at the crack-tip areas on the formation behavior of fatal cracks is discussed in terms of the microstructural evolution caused by cyclic stressing and the mixed-mode stress intensity factor. The in-plane shear mode deformation at the crack tip assisted the formation of the inclined crack paths and the unique crack face profile.
Key Engineering Materials, 2016
Fatigue tests were conducted on specimens of ultrafine grained copper produced by equal channel a... more Fatigue tests were conducted on specimens of ultrafine grained copper produced by equal channel angular pressing. The growth behavior of a fatal crack was monitored successively. The morphological features of the crack growth paths and fracture surfaces were influenced by variation of grain size and damaged areas of the crack tip, depending on the stage of progress of the fatigue damage. The change in fracture surface was discussed by considering the interrelation between the reversible plastic zone size at the crack tip and the microstructure evolved during cyclic stressing.
International Journal of Fatigue, 2016
Fatigue tests were conducted on round-bar specimens to understand the fatigue behavior of precipi... more Fatigue tests were conducted on round-bar specimens to understand the fatigue behavior of precipitatestrengthened Cu-6Ni-1.5Si alloy. Aging at 500°C for 0.5 h produced d-Ni 2 Si precipitates in the matrix, homogeneously and heterogeneously precipitated d-Ni 2 Si particles, and a precipitate-free zone around the grain boundaries. The cracks were initiated at the grain boundaries, followed by growth along the crystallographic slip planes in the adjacent grains. Crack propagation from the crack origin along the grain boundaries was occasionally observed. The physical background of fatigue damage is discussed in light of the role of microstructure on the behavior of fatigue cracks.
Scientific reports, Jan 30, 2015
The development of Cu-based alloys with high-mechanical properties (strength, ductility) and elec... more The development of Cu-based alloys with high-mechanical properties (strength, ductility) and electrical conductivity plays a key role over a wide range of industrial applications. Successful design of the materials, however, has been rare due to the improvement of mutually exclusive properties as conventionally speculated. In this paper, we demonstrate that these contradictory material properties can be improved simultaneously if the interfacial energies of heterogeneous interfaces are carefully controlled. We uniformly disperse γ-Al2O3 nanoparticles over Cu matrix, and then we controlled atomic level morphology of the interface γ-Al2O3//Cu by adding Ti solutes. It is shown that the Ti dramatically drives the interfacial phase transformation from very irregular to homogeneous spherical morphologies resulting in substantial enhancement of the mechanical property of Cu matrix. Furthermore, the Ti removes impurities (O and Al) in the Cu matrix by forming oxides leading to recovery of t...
Journal of Nanoscience and Nanotechnology, 2014
Under near-equilibrium solidification conditions, the Co-17.8 wt%Gd eutectic alloy forms rod-like... more Under near-equilibrium solidification conditions, the Co-17.8 wt%Gd eutectic alloy forms rod-like eutectic microstructure of (αCo) solid solution and Co17Gd2 compound. When the solidification condition is far from the equilibrium, the rapid growth of nano-eutectic in Co-17.8 wt%Gd alloy ribbons is realized by the single-roller techniques. The average granular size (d) of nano-eutectic in the center of ribbons varies with the increase of wheel speed (V), d = 510.36-25.51 V+0.44 V2. XRD results of ribbons at different wheel speeds indicate that, with the rise of wheel speed, the main peak of Co17Gd2 compound becomes more and more notable, whereas the main peak of (αCo) solid solution tends to reduce. Along the length direction, the Co-17.8 wt%Gd alloy ribbons have the negative magnetostrictive strain. The magnetostrictive strain enhances with the increase of wheel speed. At the wheel speed of 40 m/s, the magnetostrictive coefficient of ribbons is measured to be - 733 ppm at the magnetic field of 6 kOe. The influence of the wheel speed and the magnetic field on the maanetostrictive coefficient is discussed.
Materials Science Forum, 2007
The accumulative roll bonding (ARB) process is one of the methods to refine the grain size of met... more The accumulative roll bonding (ARB) process is one of the methods to refine the grain size of metallic materials. The ARB process up to 8 cycles was performed for the pure Cu and Cu- Fe-P (PMC-90) alloy at ambient temperature under no lubricant conditions. In the pure Cu, the nano-sized grains were formed after third cycle with an average grain size of 200nm. Once the 200 nm grains formed, further reduction in the grain size was not observed up to the 8 ARB process cycles. On the other hand, the formation of the stable nano-sized grains in PMC-90 alloy was retarded compared to the pure Cu due to the alloying elements. For both alloys, the tensile strength values increased drastically in the initial stage of ARB process. The tensile strength values of both alloys tended to saturate after the third ARB process cycle. The tensile elongation value greatly decreased by 1 cycle of ARB process due to the strain hardening. After the third cycle of ARB process, each alloy showed a gradual in...
Materials Science Forum, 2008
Effects of strain rate on the microstructure evolution and thermal stability of 1050 commercial p... more Effects of strain rate on the microstructure evolution and thermal stability of 1050 commercial pure aluminum processed by means of split Hopkinson pressure bar (SHPB) and Instron−3369 mechanical testing machine were investigated. Samples in the deformed state and after various annealing treatments at 423−523 K (150−250 °C) for 1 h were characterized by TEM and hardness test. The result reveals that the samples in the deformed state were mainly composed of elongated subgrains/cells with high density of dislocations. Microstructures of the quasi-static compressed aluminum were quite stable throughout the temperature range studied, and no significant grain growth was observed. However, for the dynamic impacted one, recrystallized grains with an average grain size of 4.7 μm were evolved after annealing at 523 K (250 °C) for 1 h. It is suggested that the annealing behavior of this dynamic deformed aluminum is a continuous process of grain coarsening, rather than the traditional discontinuous recrystallization for the quasi-static compressed aluminum.
Key Engineering Materials, 2014
Two Cu samples: oxygen-free copper (99.99 wt% Cu) and deoxidized low-phosphorous copper (99.9 wt%... more Two Cu samples: oxygen-free copper (99.99 wt% Cu) and deoxidized low-phosphorous copper (99.9 wt% Cu) were processed by equal channel angular pressing (ECAP). After the ECAP processing using 4 passes, equiaxed grains (~300 nm grain size) and elongated grains were formed for both samples. Fatigue strength of ultrafine grained Cu was enhanced by the addition of trace impurities. The formation behavior of surface damage and the change in surface hardness during stressing were monitored. A close relationship was observed between the change in hardness and the formation behavior of damage. The effect of trace impurities on the fatigue damage was discussed from the viewpoints of the grain coarsening and the crack initiation/growth behaviors.
Scripta Metallurgica et Materialia, 1995
It is of interest how to design the Al-Ti-V-Zr system and optimize the compositions of added tran... more It is of interest how to design the Al-Ti-V-Zr system and optimize the compositions of added transition elements to minimize the lattice misfit, and thus an interfacial energy, and maximize the coarsening resistance and, at the same time, optimize the volume fraction of the precipitated stable D0{sub 23} Al{sub 3}M phase. These all can be beneficial to the high temperature strength. The coarsening kinetics of the L1{sub 2} precipitate in the present study were very slow. Furthermore, the transformation of the L1{sub 2} phase to the D0{sub 23} phase was not observed. The free energy change for the L1{sub 2}-D0{sub 23} transformation was probably reduced due to the reduction in lattice misfit and strain. In the previous works, the authors designed alloys assuming the stable DO{sub 23} phase would play an active role in the aging condition, but this prediction was not observed. Instead, L1{sub 2} precipitates were dominant. Owing to the low coarsening rate and these high thermal stability of the precipitated phases, Al-Ti-V-Zr systems show promise as bases for high-temperature high-strength Al alloys.
ACS Applied Electronic Materials
Bulletin of the American Physical Society, 2019
Acta Materialia, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Philosophical Magazine Letters, 2020
The effect of deformation before aging on discontinuous precipitation in Cu-4.75wt%Ni-1.13wt%Si a... more The effect of deformation before aging on discontinuous precipitation in Cu-4.75wt%Ni-1.13wt%Si and Cu-6wt%Ni-1.42wt%Si alloys after solution treatment was investigated. Two kinds of deformation, one under and the other over the uniform deformation limit were implemented after solution treatment. With increasing deformation strain in both alloys, the discontinuous precipitation is accelerated and the aging time for a fully covered region by discontinuous precipitation is shortened. However, the Cu-6wt%Ni-1.42wt%Si alloy deformed under the uniform deformation limits showed an enhanced discontinuous precipitation compared to that for the alloy deformed over the uniform deformation limit. The deformation defects including dislocations and shear bands play the role of encouraging discontinuous precipitation. The shear bands formed during prior deformation beyond the necking point could provide sites for discontinuous precipitation initiation in the early stages of annealing However, shear bands tend to hinder the advance of discontinuous precipitation with further aging in the Cu-Ni-Si alloy with a high content of Ni and Si.
Progress in Materials Science, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The Proceedings of the Materials and processing conference, 2018
Journal of Alloys and Compounds, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Korean Journal of Metals and Materials, 2019
Cu-Ti alloys were strengthened by Cu 4 Ti intermetallic compound precipitation in a Cu matrix dur... more Cu-Ti alloys were strengthened by Cu 4 Ti intermetallic compound precipitation in a Cu matrix during aging. The Cu-3.5 wt% Ti(Cu-4.6 at% Ti) alloys without deformation and with uniform and nonuniform deformation were aged at 450 o C for various times after solution treatment at 885 o C. The uniformly and non-uniformly deformed alloys show slip and shear band formation in the matrix, respectively. The deformation bands, slip or shear bands, were still maintained even after 12 hours of aging at 450 o C. The conductivity of all the specimens continuously increased, but the hardness reached the peak value and then decreased during aging. The hardness and conductivity of the specimen with shear bands had a higher value than the specimens without deformation and with slip bands. Additionally, the time to reach peak hardness of the specimen with shear bands was shortened to 30 minutes compared to 720 and 1440 minutes for specimens with slip bands and without deformation bands, respectively. The highest combination value of conductivity and hardness, 16.8% IACS and 302 Hv, was obtained in the specimen with shear bands after aging for 360 minutes.
The Proceedings of the Materials and Mechanics Conference, 2008
Egual channel angula 厂 pre ． ∬η 9， Cop ρ er ． Shea广 わ α ηみ ， Sttrface c 厂 ack
Materials Science and Engineering: A, 2017
A technique of fabricating ultrafine grained Fe-based shape memory alloys with high strength via ... more A technique of fabricating ultrafine grained Fe-based shape memory alloys with high strength via differential speed rolling with high speed ratios of 2-3.8 and subsequent annealing was proposed. The processed alloy exhibited a markedly higher recovery stress compared to the same alloy with a coarse grain size.
Journal of the Society of Materials Science, Japan, 2004
International Journal of Fatigue, 2016
Abstract The formation mechanism of inclined fatigue-cracks in ultrafine-grained Cu processed by ... more Abstract The formation mechanism of inclined fatigue-cracks in ultrafine-grained Cu processed by equal channel angular pressing was studied by using a partially notched specimen in which a fatal natural crack was introduced, to a specific site of the smooth surface was feasible regardless of microstructural inhomogeneity caused by the processing. The crack growth direction depended on the location along the circumferential direction of the round bar specimen and on the applied stress amplitudes. The role of the microstructure and deformation mode at the crack-tip areas on the formation behavior of fatal cracks is discussed in terms of the microstructural evolution caused by cyclic stressing and the mixed-mode stress intensity factor. The in-plane shear mode deformation at the crack tip assisted the formation of the inclined crack paths and the unique crack face profile.
Key Engineering Materials, 2016
Fatigue tests were conducted on specimens of ultrafine grained copper produced by equal channel a... more Fatigue tests were conducted on specimens of ultrafine grained copper produced by equal channel angular pressing. The growth behavior of a fatal crack was monitored successively. The morphological features of the crack growth paths and fracture surfaces were influenced by variation of grain size and damaged areas of the crack tip, depending on the stage of progress of the fatigue damage. The change in fracture surface was discussed by considering the interrelation between the reversible plastic zone size at the crack tip and the microstructure evolved during cyclic stressing.
International Journal of Fatigue, 2016
Fatigue tests were conducted on round-bar specimens to understand the fatigue behavior of precipi... more Fatigue tests were conducted on round-bar specimens to understand the fatigue behavior of precipitatestrengthened Cu-6Ni-1.5Si alloy. Aging at 500°C for 0.5 h produced d-Ni 2 Si precipitates in the matrix, homogeneously and heterogeneously precipitated d-Ni 2 Si particles, and a precipitate-free zone around the grain boundaries. The cracks were initiated at the grain boundaries, followed by growth along the crystallographic slip planes in the adjacent grains. Crack propagation from the crack origin along the grain boundaries was occasionally observed. The physical background of fatigue damage is discussed in light of the role of microstructure on the behavior of fatigue cracks.
Scientific reports, Jan 30, 2015
The development of Cu-based alloys with high-mechanical properties (strength, ductility) and elec... more The development of Cu-based alloys with high-mechanical properties (strength, ductility) and electrical conductivity plays a key role over a wide range of industrial applications. Successful design of the materials, however, has been rare due to the improvement of mutually exclusive properties as conventionally speculated. In this paper, we demonstrate that these contradictory material properties can be improved simultaneously if the interfacial energies of heterogeneous interfaces are carefully controlled. We uniformly disperse γ-Al2O3 nanoparticles over Cu matrix, and then we controlled atomic level morphology of the interface γ-Al2O3//Cu by adding Ti solutes. It is shown that the Ti dramatically drives the interfacial phase transformation from very irregular to homogeneous spherical morphologies resulting in substantial enhancement of the mechanical property of Cu matrix. Furthermore, the Ti removes impurities (O and Al) in the Cu matrix by forming oxides leading to recovery of t...
Journal of Nanoscience and Nanotechnology, 2014
Under near-equilibrium solidification conditions, the Co-17.8 wt%Gd eutectic alloy forms rod-like... more Under near-equilibrium solidification conditions, the Co-17.8 wt%Gd eutectic alloy forms rod-like eutectic microstructure of (αCo) solid solution and Co17Gd2 compound. When the solidification condition is far from the equilibrium, the rapid growth of nano-eutectic in Co-17.8 wt%Gd alloy ribbons is realized by the single-roller techniques. The average granular size (d) of nano-eutectic in the center of ribbons varies with the increase of wheel speed (V), d = 510.36-25.51 V+0.44 V2. XRD results of ribbons at different wheel speeds indicate that, with the rise of wheel speed, the main peak of Co17Gd2 compound becomes more and more notable, whereas the main peak of (αCo) solid solution tends to reduce. Along the length direction, the Co-17.8 wt%Gd alloy ribbons have the negative magnetostrictive strain. The magnetostrictive strain enhances with the increase of wheel speed. At the wheel speed of 40 m/s, the magnetostrictive coefficient of ribbons is measured to be - 733 ppm at the magnetic field of 6 kOe. The influence of the wheel speed and the magnetic field on the maanetostrictive coefficient is discussed.
Materials Science Forum, 2007
The accumulative roll bonding (ARB) process is one of the methods to refine the grain size of met... more The accumulative roll bonding (ARB) process is one of the methods to refine the grain size of metallic materials. The ARB process up to 8 cycles was performed for the pure Cu and Cu- Fe-P (PMC-90) alloy at ambient temperature under no lubricant conditions. In the pure Cu, the nano-sized grains were formed after third cycle with an average grain size of 200nm. Once the 200 nm grains formed, further reduction in the grain size was not observed up to the 8 ARB process cycles. On the other hand, the formation of the stable nano-sized grains in PMC-90 alloy was retarded compared to the pure Cu due to the alloying elements. For both alloys, the tensile strength values increased drastically in the initial stage of ARB process. The tensile strength values of both alloys tended to saturate after the third ARB process cycle. The tensile elongation value greatly decreased by 1 cycle of ARB process due to the strain hardening. After the third cycle of ARB process, each alloy showed a gradual in...
Materials Science Forum, 2008
Effects of strain rate on the microstructure evolution and thermal stability of 1050 commercial p... more Effects of strain rate on the microstructure evolution and thermal stability of 1050 commercial pure aluminum processed by means of split Hopkinson pressure bar (SHPB) and Instron−3369 mechanical testing machine were investigated. Samples in the deformed state and after various annealing treatments at 423−523 K (150−250 °C) for 1 h were characterized by TEM and hardness test. The result reveals that the samples in the deformed state were mainly composed of elongated subgrains/cells with high density of dislocations. Microstructures of the quasi-static compressed aluminum were quite stable throughout the temperature range studied, and no significant grain growth was observed. However, for the dynamic impacted one, recrystallized grains with an average grain size of 4.7 μm were evolved after annealing at 523 K (250 °C) for 1 h. It is suggested that the annealing behavior of this dynamic deformed aluminum is a continuous process of grain coarsening, rather than the traditional discontinuous recrystallization for the quasi-static compressed aluminum.
Key Engineering Materials, 2014
Two Cu samples: oxygen-free copper (99.99 wt% Cu) and deoxidized low-phosphorous copper (99.9 wt%... more Two Cu samples: oxygen-free copper (99.99 wt% Cu) and deoxidized low-phosphorous copper (99.9 wt% Cu) were processed by equal channel angular pressing (ECAP). After the ECAP processing using 4 passes, equiaxed grains (~300 nm grain size) and elongated grains were formed for both samples. Fatigue strength of ultrafine grained Cu was enhanced by the addition of trace impurities. The formation behavior of surface damage and the change in surface hardness during stressing were monitored. A close relationship was observed between the change in hardness and the formation behavior of damage. The effect of trace impurities on the fatigue damage was discussed from the viewpoints of the grain coarsening and the crack initiation/growth behaviors.
Scripta Metallurgica et Materialia, 1995
It is of interest how to design the Al-Ti-V-Zr system and optimize the compositions of added tran... more It is of interest how to design the Al-Ti-V-Zr system and optimize the compositions of added transition elements to minimize the lattice misfit, and thus an interfacial energy, and maximize the coarsening resistance and, at the same time, optimize the volume fraction of the precipitated stable D0{sub 23} Al{sub 3}M phase. These all can be beneficial to the high temperature strength. The coarsening kinetics of the L1{sub 2} precipitate in the present study were very slow. Furthermore, the transformation of the L1{sub 2} phase to the D0{sub 23} phase was not observed. The free energy change for the L1{sub 2}-D0{sub 23} transformation was probably reduced due to the reduction in lattice misfit and strain. In the previous works, the authors designed alloys assuming the stable DO{sub 23} phase would play an active role in the aging condition, but this prediction was not observed. Instead, L1{sub 2} precipitates were dominant. Owing to the low coarsening rate and these high thermal stability of the precipitated phases, Al-Ti-V-Zr systems show promise as bases for high-temperature high-strength Al alloys.