Characterization of the different precipitates developed in supersaturated Al–1.12Mg2Si–0.35Si (mass%) alloy by thermoelectric power (TEP) and electrical resistivity (ER) measurements was considered. The effect of precipitation of coherent, semi-coherent and noncoherent phases on the TEP was found impressive in describing different precipitates. Upon growing and coherency loss of b0 particles, the TEP increases to reach a maximum value. TEP begins to approach a stable value by the formation of the equilibrium b (Mg2Si) precipitates and then stabilizes with the complete growth of more stable precipitates b phase and Si particles. The first-order coefficient a of the ER–temperature dependence was found dominating in the temperature range 300–635 K. Above this temperature range, the second-order coefficient b starts sharing effectively the resistivity–temperature dependence. Furthermore, it has been shown that the range of temperature in which the first-order coefficient a is dominating slightly increases after slow cooling twice to the room temperature in two successive runs. Correlation of a and b with the lattice rigidity of the alloy under investigation was established. Quenching and slow cooling affect strongly the observed correlation. All measurements in the present investigation were taken under non-isothermal conditions.

Characterization of the different precipitates developed in supersaturated Al–1.12Mg2Si–0.35Si (mass%) alloy by thermoelectric power (TEP) and electrical resistivity (ER) measurements was considered. The effect of precipitation of coherent, semi-coherent and noncoherent phases on the TEP was found impressive in describing different precipitates. Upon growing and coherency loss of b0 particles, the TEP increases to reach a maximum value. TEP begins to approach a stable value by the formation of the equilibrium b (Mg2Si) precipitates and then stabilizes with the complete growth of more stable precipitates b phase and Si particles. The first-order coefficient a of the ER–temperature dependence was found dominating in the temperature range 300–635 K. Above this temperature range, the second-order coefficient b starts sharing effectively the resistivity–temperature dependence. Furthermore, it has been shown that the range of temperature in which the first-order coefficient a is dominating slightly increases after slow cooling twice to the room temperature in two successive runs. Correlation of a and b with the lattice rigidity of the alloy under investigation was established. Quenching and slow cooling affect strongly the observed correlation. All measurements in the present investigation were taken under non-isothermal conditions.

Characterization of the different precipitates developed in supersaturated Al–1.12Mg2Si–0.35Si (mass%) alloy by thermoelectric power (TEP) and electrical resistivity (ER) measurements was considered. The effect of precipitation of coherent, semi-coherent and noncoherent phases on the TEP was found impressive in describing different precipitates. Upon growing and coherency loss of b0 particles, the TEP increases to reach a maximum value. TEP begins to approach a stable value by the formation of the equilibrium b (Mg2Si) precipitates and then stabilizes with the complete growth of more stable precipitates b phase and Si particles. The first-order coefficient a of the ER–temperature dependence was found dominating in the temperature range 300–635 K. Above this temperature range, the second-order coefficient b starts sharing effectively the resistivity–temperature dependence. Furthermore, it has been shown that the range of temperature in which the first-order coefficient a is dominating slightly increases after slow cooling twice to the room temperature in two successive runs. Correlation of a and b with the lattice rigidity of the alloy under investigation was established. Quenching and slow cooling affect strongly the observed correlation. All measurements in the present investigation were taken under non-isothermal conditions.

In the present article, kinetics of the clustering processes in AF/C489 Alloyin the early stages of aging was probably contributed by coalescence of Cu-vacancy, Li-vacancy and Zn-vacancy complexes to form Li–Cu-Zn-vacancy clusters. The high value of the activation energy indicate that the driving force of the clustering process is high. In Li-containing aluminium alloy, preferential clustering of lithium-vacancy pairs is thought to occur during solution treatment and quenching, since lithium possesses a higher vacancy binding energy than zinc or magnesium does. The diffusion of Zn and Mg atoms is slowed down because of preferential formation of Li-vacancy aggregates in the alloy, when Li atoms are present in the form of solution. The activation energy associated with the precipitation of the θ` phase was found 61.63 kJ mol−1. Accordingly, the mechanism of the precipitation of θ` (Al2Cu) phase controlled by both migrations of Li and Cu atoms in the Al matrix. Vacancies bound to lithium atoms make it difficult for diffusion or aggregate to grain boundaries, this is one of the main reasons of forming narrow precipitate-free zones in present Li-containing alloy. The results evidently indicate that Li atoms slow down the diffusion of Zn and Mg atoms and vacancies, and thus the segregation of them to grain boundaries has been restricted. The micro hardness was found to increase as a result of the precipitate of δ` (Al3Li) and T1(Al2CuLi) precipitates.

In the present article, kinetics of the clustering processes in AF/C489 Alloyin the early stages of aging was probably contributed by coalescence of Cu-vacancy, Li-vacancy and Zn-vacancy complexes to form Li–Cu-Zn-vacancy clusters. The high value of the activation energy indicate that the driving force of the clustering process is high. In Li-containing aluminium alloy, preferential clustering of lithium-vacancy pairs is thought to occur during solution treatment and quenching, since lithium possesses a higher vacancy binding energy than zinc or magnesium does. The diffusion of Zn and Mg atoms is slowed down because of preferential formation of Li-vacancy aggregates in the alloy, when Li atoms are present in the form of solution. The activation energy associated with the precipitation of the θ` phase was found 61.63 kJ mol−1. Accordingly, the mechanism of the precipitation of θ` (Al2Cu) phase controlled by both migrations of Li and Cu atoms in the Al matrix. Vacancies bound to lithium atoms make it difficult for diffusion or aggregate to grain boundaries, this is one of the main reasons of forming narrow precipitate-free zones in present Li-containing alloy. The results evidently indicate that Li atoms slow down the diffusion of Zn and Mg atoms and vacancies, and thus the segregation of them to grain boundaries has been restricted. The micro hardness was found to increase as a result of the precipitate of δ` (Al3Li) and T1(Al2CuLi) precipitates.

In the present article, kinetics of the clustering processes in AF/C489 Alloyin the early stages of aging was probably contributed by coalescence of Cu-vacancy, Li-vacancy and Zn-vacancy complexes to form Li–Cu-Zn-vacancy clusters. The high value of the activation energy indicate that the driving force of the clustering process is high. In Li-containing aluminium alloy, preferential clustering of lithium-vacancy pairs is thought to occur during solution treatment and quenching, since lithium possesses a higher vacancy binding energy than zinc or magnesium does. The diffusion of Zn and Mg atoms is slowed down because of preferential formation of Li-vacancy aggregates in the alloy, when Li atoms are present in the form of solution. The activation energy associated with the precipitation of the θ` phase was found 61.63 kJ mol−1. Accordingly, the mechanism of the precipitation of θ` (Al2Cu) phase controlled by both migrations of Li and Cu atoms in the Al matrix. Vacancies bound to lithium atoms make it difficult for diffusion or aggregate to grain boundaries, this is one of the main reasons of forming narrow precipitate-free zones in present Li-containing alloy. The results evidently indicate that Li atoms slow down the diffusion of Zn and Mg atoms and vacancies, and thus the segregation of them to grain boundaries has been restricted. The micro hardness was found to increase as a result of the precipitate of δ` (Al3Li) and T1(Al2CuLi) precipitates.

The precipitation processes in quenched Al-Li (2090) alloy from the solid solution state , then heat treated at Ta = 460 K and 600 K have been investigated by Vickers Hardness (HV) measurements and Differential Scanning Calorimetry (DSC). The overall activation energies associated with the transformation processes are evaluated using the DSC thermograms and accordingly the kinetics of these processes has been characterized. Both Electron Microscopy (scanning SEM and transmission TEM) and X-Ray Diffraction (XRD) are performed to clarify and confirm the obtained results. The -Phase (Al3Li) and the T2-phase (Al6CuLi3) are exist in the alloy in addition to TB (Al7Cu4Li) phase in the Al - matrix. Such existence is actively contributing to the strengthening of the alloy. Analysis of the results indicates coarsening of the -phase is, preferable, at the grain boundaries. The lattice parameters and the particle size (D) of the existing phases could be calculated using the Full-Prof computer program. The D of the -phase was found in the nano-scaled range. In addition, the presence of Li in the alloy reduced the material density. The reduction in density by all means is a reduction in the fuel consumption if the material is used in aircraft and automobile industries. In its turn, a fuel consumption reduction minimizes environmental pollution.

The precipitation processes in quenched Al-Li (2090) alloy from the solid solution state , then heat treated at Ta = 460 K and 600 K have been investigated by Vickers Hardness (HV) measurements and Differential Scanning Calorimetry (DSC). The overall activation energies associated with the transformation processes are evaluated using the DSC thermograms and accordingly the kinetics of these processes has been characterized. Both Electron Microscopy (scanning SEM and transmission TEM) and X-Ray Diffraction (XRD) are performed to clarify and confirm the obtained results. The -Phase (Al3Li) and the T2-phase (Al6CuLi3) are exist in the alloy in addition to TB (Al7Cu4Li) phase in the Al - matrix. Such existence is actively contributing to the strengthening of the alloy. Analysis of the results indicates coarsening of the -phase is, preferable, at the grain boundaries. The lattice parameters and the particle size (D) of the existing phases could be calculated using the Full-Prof computer program. The D of the -phase was found in the nano-scaled range. In addition, the presence of Li in the alloy reduced the material density. The reduction in density by all means is a reduction in the fuel consumption if the material is used in aircraft and automobile industries. In its turn, a fuel consumption reduction minimizes environmental pollution.

The precipitation processes in quenched Al-Li (2090) alloy from the solid solution state , then heat treated at Ta = 460 K and 600 K have been investigated by Vickers Hardness (HV) measurements and Differential Scanning Calorimetry (DSC). The overall activation energies associated with the transformation processes are evaluated using the DSC thermograms and accordingly the kinetics of these processes has been characterized. Both Electron Microscopy (scanning SEM and transmission TEM) and X-Ray Diffraction (XRD) are performed to clarify and confirm the obtained results. The -Phase (Al3Li) and the T2-phase (Al6CuLi3) are exist in the alloy in addition to TB (Al7Cu4Li) phase in the Al - matrix. Such existence is actively contributing to the strengthening of the alloy. Analysis of the results indicates coarsening of the -phase is, preferable, at the grain boundaries. The lattice parameters and the particle size (D) of the existing phases could be calculated using the Full-Prof computer program. The D of the -phase was found in the nano-scaled range. In addition, the presence of Li in the alloy reduced the material density. The reduction in density by all means is a reduction in the fuel consumption if the material is used in aircraft and automobile industries. In its turn, a fuel consumption reduction minimizes environmental pollution.

The aim of the present paper is to investigate the mechanical properties and precipitation behavior of the Al– 4.4Cu–1.5Mg-0.6Mn-0.25Si (wt%) alloy as a function of heat treatment. The X-Ray diffraction analysis (XRD), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Microhardness Vickers test (HV) have been used to examine the effects of microalloying and the origins of hardening precipitates during heat treatment. The combined application of these techniques is particularly important in the study of nanoscale precipitation processes. The solute clusters precede the formation of GP zones or precipitation and have a defining role on the nature and kinetics of the subsequent precipitation processes. The lower values of the activation energy of the precipitate particles indicate that, the driving force of the clustering process is low and the Cu addition to this kind of alloys enhances the clustering process.