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Title: The preparation and properties of a glass-ceramic with an aligned microstructure
Author: Atkinson, David Ian Heaton
ISNI:       0000 0001 3431 9528
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1975
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The work described in this thesis was performed on glass-ceramics in which a random arrangement of crystals is grown as a dispersed phase. The physical properties of this material are isotropic. The technique of hot extrusion has been used to produce a material with an aligned crystal microstructure in a Li2O-SiO2 glass-ceramic. The extruded material consists of a glass matrix and two crystalline phases; one of these phases is aligned morphologically and crystallographically parallel to the extrusion axis. The microstructure of this extruded material was analysed statistically in terms of the volume fraction of crystalline phases, the mean crystal- crystal spacing and the distribution function of the number of crystals N(Ɵ), making an angle Ɵ with a reference direction. Control specimens of the same composition heat-treated at the same temperature and for the same time as the extruded samples were also analysed statistically. The following physical properties were measured on the control and extruded specimens: (i) the coefficient of thermal expansion (ii) Young's modulus, rupture strength and microhardness (iii) Resistivity, dielectric constant and loss tangent. In the case of the extruded samples these measurements were made in directions parallel and perpendicular to the extrusion axis; the coefficient of thermal expansion, the mechanical properties and the resistivity were found to be anisotropic for these specimens.
Supervisor: Not available Sponsor: General Electric Company ; Science Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QC Physics ; TA Engineering (General). Civil engineering (General) ; TP Chemical technology