Eutectic fibre

As Fig. 20.7 shows, if DS eutectics ( DSEs ) prove successful, they will allow the metal temperature to be increased by =100°C above conventional DS nickel alloys, and the inlet temperature by =200°C (because of a temperature scaling effect caused by the blade cooling). Further improvements in alloy design are under way in which existing nickel alloys and DS eutectics are being blended to give a fibre-reinforced structure with precipitates in the matrix. 

In order to achieve efficient build-up to heavy depths when dyeing cellulose acetate at 80 °C it is customary, particularly for navy blues, to use a mixture of two or more components of similar hue. If these behave independently, each will give its saturation solubility in the fibre. In practice, certain mixtures of dyes with closely related structures are 20-50% less soluble in cellulose acetate than predicted from the sum of their individual solubilities [87]. Dyes of this kind form mixed crystals in which the components are able to replace one another in the crystal lattice. The melting point depends on composition, varying gradually between those of the components, and the mixed crystals exhibit lower solubility than the sum of solubilities of the component dyes [88]. Dyes of dissimilar molecular shape do not form mixed crystals, the melting point curve of the mixture shows a eutectic point and they behave additively in mixtures with respect to solubility in water and in the fibre. 

Related to ionic liquids are substances known as deep eutectic solvents or mixtures. A series of these materials based on choline chloride (HOCH2CH2NMe3Cl) and either zinc chloride or urea have been reported (Abbott et al., 2002 2003). The urea/choline chloride material has many of the advantages of more well-known ionic liquids (e.g. low volatility), but can be sourced from renewable feedstocks, is non-toxic and is readily biodegradable. However, it is not an inert solvent and this has been exploited in the functionalisation of the surface of cellulose fibres in cotton wool (Abbott et al, 2006). Undoubtedly, this could be extended to other cellulose-based materials, biopolymers, synthetic polymers and possibly even small molecules. 

Tungsten diselenide Gallium/indium eutectic, carbon fibre/polyimide 193... 

A particular type of fibre-reinforced composite is the directionally solidified eutectics in which matrix and reinforcement are made in one single process from one or two different materials. The reinforcement usually has the form of plates or rods and their orientation may be designed and controlled in the solidification process. Only the volume fraction of the reinforcement cannot be designed arbitrarily and is determined by the applied technological processes. 

In bivariant eutectic, the matrix has a FCC structure and oi Mo fibre has a BCC structure. This relationship of crystal structures in co-existing phases assumes a relatively simple preferred orientation relation between them. Using the TEM method, crystallographic orientation relationship of the co-existing phases was obtained ... 

The distribution of solutes in co-existing phases was specified. It was found that there is a relatively low solubility of all elements (Ni, A1 and Ta) in Mo fibres, even though their solubility is high in correspoding binary equilibrium diagrams with molybdenum. On the other hand. Mo solubility in intermetallic y phase in ternary y/y -a eutectic is 4 at.% [2]. In bivariant y -a eutectic this value is reduced to a half. The presence of Ta decreases Mo solubility in intermetallic y phase. 

Fig. 6.7 The relative surface areas for lamellar eutectic arrangements, S i, compared with those of fibres. So, or vice versa, as functions of the volume proportions (a) is the volume fraction of the minor constituent (h)is the volume fractmt of the major constituent. Eutectic alloys having the lamellar habit are marked X and those with a fibrous habit arc marked O Hellawell ).

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