Papers by Keyword: Solute

Abstract: On the basis of the quantitative structure-property relationship (QSPR) method and the quantum chemical descriptors including molecular van der Waals volume (Vmc), dipole moments (μ), the most negative formal charge in solute molecule (q-), and the most positive formal charge on a hydrogen atom in solute molecule (q+) of organic compounds, the values of activity coefficients at infinite dilution, , for 16 solutes in ionic liquid 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]) at 323.15 K were correlated with the descriptors. The result showed that the QSPR model had a good correlation and could successfully describe . The quantitative relationship between organic molecular structure and in [EMIM][DEP] was obtained and the correlation parameters were analyzed to understand the interactions that affect activity coefficients at infinite dilution.

Abstract: Base on structural descriptors including dipole moments (μ), Energy gap (∆ε), hydration energy (∆H), and hydrophobic parameter lg P of 25 organic solutes, the quantitative structure-property relationship (QSPR) method was used to correlate the values of activity coefficients at infinite dilution, , for the solutes in ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) at 323.15 K. The result showed that the QSPR model had a good correlation and could successfully describe . The quantitative relationship between organic molecular structure and in [EMIM][BF4] was obtained and the correlation parameters were analyzed to understand the interactions that affect activity coefficients at infinite dilution.

Abstract: The cube texture in rolled and annealed fcc metals and alloys has long fascinated metallurgists because of its high symmetry and extreme sharpness. This paper demonstrates and analyses the texture perfection that is developed in a copper sample. Reasons that have been advanced to explain the development of the texture during recrystallisation and grain growth are discussed. Orientation selectivity is favoured during growth but more particularly in the nucleation stage. Especial attention is paid to the rapid recovery which cube oriented crystals undergo on heating after plane strain deformation and which is the basis for its uniquely preferential nucleation. Various metallurgical factors are known to affect the strength of the cube texture in practice and explanations for some of these are presented.

Abstract: IR spectra of mixtures of light and heavy water seem to provide a clear evidence for the existence of substructures, each of which may be assigned to a particular kind of water molecule on the basis of their correlation with the local environment. These substructures have been related to three different populations named correlated, non correlated and intermediate according to their degree of correlation. Experimental data analysis show that, in a mixture of H2O-D2O, each population participates differently to the solution process.

Abstract: The pure aluminized layer and RE-aluminized layer on industrial pure iron were prepared by hot dip aluminizing method, and the thickness and composition of the layer were investigated by means of scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The results showed that the RE was permeated into the alloy layer after hot dip RE-aluminizing and the thickness of the alloy layer increases by about 30% as against hot dip pure aluminizing. The binding energy between the vacancy and aluminum atom was calculated. According to the energy condition of the solute-vacancy complex diffusion, it points out that the solute-vacancy complex diffusion is the main mechanism of aluminum atoms diffusion in hot dip RE-aluminizing and the main reason why the thickness of alloy layer increases after hot dip RE-aluminizing.

Abstract: The microstructure of directional solidified Al-Zn-Mg alloys is characterized and predicted by means of thermal analysis data, multicomponent equations for dendrite growth and data from ternary AlZnMg phase diagram. The resulting microstructure consists of α-Al dendrites with τ precipitates and eutectic in interdendritic regions. Predictions show that at growth velocities up to 9 x 10-4 m/s, the α-Al and τ intermetallic grew simultaneously. Predictions for solute concentration according to the model for dendrite solidification of multicomponent alloys with unequal liquid diffusion coefficients show a good agreement with experimental results.

Abstract: The effect of copper content on dynamic grain growth in Al-Cu-Zr system was investigated by studying the microstructural development and texture evolution during uniaxial tensile deformation of Al-2wt%Cu-0.3wt.%Zr and Al-4wt%Cu-0.4wt.%Zr alloys at 450°C with a strain rate of 10-3s-1, with a similar initial microstructure in both materials. The initial microstructure consisted of layers of different orientations, the layers being separated by high-angle grain boundaries with low-angle boundaries separating grains within the layers. The initial grain spacing was about 5
m and the texture was typical of rolled aluminium alloys. The 4wt.%Cu alloy gave a higher strain rate sensitivity index, m, and a greater ductility compared to the low copper content alloy. An increase in grain size occurred in both materials due to deformation, but this dynamic grain growth (DGG) was much greater in the material with the higher copper content. This was associated with a more rapid conversion of low-angle boundaries to high angle ones in the 4wt%Cu material which is consistent with changes in crystallographic texture occurring during deformation.

Abstract: This paper contains a review of microstructural through-process modelling (TPM) and the particular role of ingot metallurgy from an industrial perspective, focusing on recent advances in solidification theory, solidification and homogenisation software, and software environments that allow models to interface. To illustrate how as-cast microstructure can impact on downstream processing steps, a sensitivity analysis has been performed on an AA1xxx alloy using an in-house homogenisation model. Thus, knowledge gaps in theory and model application are highlighted.

Abstract: This paper examines the challenges which are encountered when using electrical resistivity measurements for characterization of microstructures in aluminum alloys. Experimental examples are provided of electrical resistivity studies conducted on two aluminum alloys, a heattreatable alloy (AA6111) and a non-heat-treatable alloy (AA5754), which demonstrate how the technique can be used to characterize changes in the microstructure. Results on AA6111 show that the dependence of the measurement on solute atoms and fine scale precipitates makes deconvolution of the resistivity signal non-trivial and therefore, utilization of supplementary technique(s) in conjunction with electrical resistivity measurements is essential. In the next example, room temperature electrical resistivity measurements as a function of cold work for AA5754 illustrate a larger resistivity contribution from dislocations in this alloy as compared to that reported for pure aluminum. The interaction of solutes and dislocations is cited as the possible source for the increased dislocation contribution.