Solvent selection is an important factor in chemical process efficiency, profitability, and environmental impact. Prediction of solvent phase behavior will allow for the identification of novel solvent systems that could offer some economic or environmental advantage. A modified cohesive energy density model is used to predict the solid-liquid-equilibria for multifunctional solids in pure and mixed solvents for rapid identification of process solvents for design of crystallization processes. Some solubility data at several temperatures are also measured to further test the general applicability of the model. Gas-expanded liquids have potential environmentally advantageous applications as pressure tunable solvents for homogeneous and heterogeneous catalytic reactions and as novel solvent media for anti-solvent crystallizations. The phase behavior of some carbon dioxide/organic binary systems is measured to provide basic process design information. Solvent selection is also an important factor in the anti-solvent precipitation of solid compounds. The influence of organic solvent on the solid-liquid equilibria for two solid pharmaceutical compounds in several carbon dioxide expanded solvents is explored. A novel solvent system is also developed that allows for homogeneous catalytic reaction and subsequent catalyst sequestration by using carbon dioxide as a miscibility switch. The fundamental biphasic solution behavior of some polar organics with water and carbon dioxide are investigated.

A systematic study of iron-based binary and multi-component alloys was undertaken to study the structural evolution in these powders as a function of milling time during mechanical alloying. Blended elemental powders of Fe100-XBX (where x = 5, 10, 17, 20, 22, 25, 37.5 and 50 at. %) and a bulk metallic glass (BMG) composition (Fe60Co8Zr10Mo5W2B15) were subjected to mechanical alloying in a SPEX 8000 mixer mill. X-ray diffraction technique was employed to study the phase evolution, crystallite size, lattice strain and also to determine the crystal structure(s) of the phases. Depending on the milling time, formation of supersaturated solid solutions, intermetallics, and amorphous phases was noted in the binary Fe-B powder mixtures. A maximum of about 22 at. % B was found to dissolve in Fe in the solid state, and formation of FeB and Fe2B intermetallics was noted in some of the powder blends. However, an interesting observation that was made, for the first time, related to the formation of a crystalline phase on continued milling of the amorphous powder in the BMG composition. This phenomenon, termed mechanical crystallization, has been explored. Reasons for the mechanical crystallization of the amorphous powder using the X-ray diffraction and electron microscopy methods have been discussed. External heat treatments of the milled powder were also conducted to study the complete crystallization behavior of the amorphous phase. Preliminary attempts were made to consolidate the milled BMG powder to bulk shape by hot isostatic pressing (HIP) and magnetic compaction techniques. Full densification was not achieved. Nanoindentation and microhardness tests were performed to characterize the mechanical properties of the glassy alloy. Nanoindentation results gave an elastic modulus of 59 GPa, lower than the expected value of 184 GPa; due to the presence of porosity in the consolidated sample. Optimization of the consolidation parameters is required to achieve a fully dense material.

The formation of liquid films is a widely known problem in aluminium heat exchanger materials. The phenomenon results in decreased brazeability along with severely deteriorated mechanical properties which might cause assembly collapse. In addition, low-melting-point elements like tin, bismuth and lead are thought to promote grain boundary sliding which is the main deformation mechanism during brazing. Their melting characteristics are not adequately reported in literature. It is therefore of great importance to examine the behaviour of these elements.The main objectives with this work is melting range determination of fin heat exchanger materials, melting detection of low-melting-point elements and calculation of tin, bismuth and lead solid-solubility in aluminium. This work does also involve distribution analysis of such elements in aluminium matrix after heat treatment.These investigations require development of a differential scanning calorimetry (DSC) technique that is applicable for analysis of aluminium fin heat exchanger material containing low-melting-point elements on ppm level. Optimization of the technique includes parameter control; like heating rate, sample mass, reproducibility and choice of crucible material. Laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) is additionally used in order to analyse solid solubility and distribution of low-melting-point elements in aluminium after heat treatment.The developed DSC technique shows a sensitivity limit in the range of 260-600 ppm. It means that it is not possible to detect melting of phases within and below that range. Solid solubility of tin was calculated for the three heat treatment temperatures, 400°C, 500°C and 625°C. Same procedure was applied on bismuth and lead. However, calculated values did not agree with Thermo-Calc. The distribution analysis indicate an exudation of trace elements i.e. diffusion toward surface during heat treatment.In conclusion, more knowledge regarding liquid films in aluminium fin heat exchanger material was obtained. Future work should be to further optimize the DSC technique for trace element analysis for concentrations below 100 ppm. The LA-ICP-MS technique is likely to improve experimentally unverified binary phase diagrams like Al-Bi, Al-Pb and Al-Sn phase diagrams. It can also be used to study exudation behaviour of liquid films.

Yes / This paper describes some underlying principles of multicomponent and high entropy alloys, and gives some examples of these materials. Different types of multicomponent alloy and different methods of accessing multicomponent phase space are discussed. The alloys were manufactured by conventional and high speed solidification techniques, and their macroscopic, microscopic and nanoscale structures were studied by optical, X-ray and electron microscope methods. They exhibit a variety of amorphous, quasicrystalline, dendritic and eutectic structures.