- Email: [email protected]
Alumina filament reinforced cement paste
refractive index. It is concluded that light scattering m a y be of particular value in the e x a m i n a t i o n of c o m p o s i t e materials including paper and anisotropic films for preferred orientation in localized regions.
of dispersion hardening and the effects of fibres on the behaviour o f dislocations in composites are discussed. A technique for the analysis of fracture
strength data for carbon fibres Jones, B. F. and Wilkins, B. J. S.
Longitudinal tensile failure of unidirectional fibrous composites Lifshitz, J. M. and Rotern, A.
Journal o f Materials Science, Vol 7, No 8, pp 861 869 (Aug 1972) A theoretical t r e a t m e n t is described o f the tensile strength o f a unidirectional fibrous composite subjected to a tensile load in the fibre direction. The fibres are assumed to have a statistical strength distribution which results in fibre failure prior to composite failure. The model derived has a failure geometry similar to that observed in tests on glass/epoxy composites.
The production of metal fibres and wires directly from the melt Butler, I. G., Kurry, W., Gillot, J. and Lux, B. Fibre Science and Technology,
Vol 5, No 4, p 243 (Oct 1972) A s u m m a r y o f the basic problem o f the production o f metal fibres directly from low viscosity melts is followed by a mathematical consideration o f the stability of liquid jets in terms o f the drop formation time. The results o f e x p e r i m e n t s on a model water jet system are correlated with this t r e a t m e n t and data concerning the variation in jet break-up length with jet velocity for molten steel and aluminium are presented. Methods o f fibre production from the melt are reviewed as a concluding section, Properties o f filaments sintered from boehmite gels Badker, P. A., Bailey, J. E. and Barker, H. A.
Transactions o f the British Ceramic Society, 1Iol 71. No 7, p 193 (Nov 1972) An investigation was made o f the microstructure and mechanical properties o f filaments ( 0 . 5 - 1 . 0 m m diameter) produced by the extrusion and sintering o f alumina hydrates pastes. The strength of the filaments was high in comparison with other types o f alumina with similar porosity and grain size. Possible explanations for this are discussed in terms o f pore size and distribution as well as of surface conditions. The densification behaviour and microstructural developm e n t of b o e h m i t e gels during sintering were investigated with a view to optimizing the fabrication techniques.
Reinforcement of structural materials by long strong fibres Kelly, A. Metallurgical Transactions,
Fo13, No 9, p 2313 (Sept 1972) The theory o f the reinforcement o f matrices by long discontinuous fibres is presented in detail. The practical implications o f the conclusions o f the analysis are discussed. Those composites in which the fibres are intended to stiffen a relatively ductile matrix, and those in which the fibres are intended to inhibit the propagation of cracks in relatively brittle matrices, are considered. The m e c h a n i s m s o f fibre reinforcement are compared with those
COMPOSITES, MARCH 1973
Fibre Science and Technology, Fol 5, No 4, p 315 (Oct 1972) It is suggested that the disadvantage o f histograms in the examination of the distribution of fibre fracture strength data, namely that very small groups m u s t be plotted to separate m o d e s which are close together, m a y be overcome by plotting derived data. It is s h o w n that when the measured fracture strength values are ranked and plotted against cumulative probability o f failure the distribution o f values can be compared with a standard unimodal distribution and any deviations from this will be revealed in one plot. This technique is being used to examine the effects of fast n e u t r o n irradiation on fibre strength.
Transverse tensile properties of an unbonded model composite Butcher, B. R. Journal o f Materials Science, Fol 7, No 8, pp 8 7 7 - 8 8 7 (Aug 1972) Unbonded model composites of steel rods in aluminium and aluminium with holes of identical geometry have been tested in tension. The c o m p l e x behaviour of Young's m o d u l u s , stress at the elastic limit and UTS have been measured and applied to real composite materials.
CERA MIC MA TRICES
aggregate was n o t very different from a concrete with voids in place o f aggregate. Formulas for estimating the compressive strength of polymer-modified mortars Amoaha, Y. Proc o f the 15th Japan
Congress on Material Research. pp 1 5 1 - 1 5 3 (1972) A "binder-void" ratio a = (V..c + V_)(V~ p u + Vw) is defined when Ve = volume of cement, lip = volume of polymer, Va = volume of air and V w = volume of water. The variation of compression strength with l / a for for various polymer modified mortars was determined experimentally. With certain exceptions the formula A log F = - - - + C Bl/a was found to apply, where F = compressive strength, A, B and C are constant.
The theoretical prediction of the cracking
stress of glass fibre reinforced inorganic cement Chan, H. C. and Patterson, W. A. Journal
o f Materials Science, Vol 7, No 8, pp 8 5 0 - 8 6 0 (Aug 1972) The cracking stress for glass fibre reinforced cement is predicted from fracture mechanics calculations and experiments appear to verify those predictions. The onset o f cracking can be increasingly suppressed with decreasing inter-fibre spacing in this type o f material.
METAL MA TRICES Chemical compatibility in metal-fiber
composites
Alumina filament reinforced cement paste Standhammer, K. P., Murr, L. E., Bailey, J. E., Barker, H. A. and Urbanowicz, C. Marinoff, C. and Reineking,V.
Transactions o f the British Ceramic Society, Fol 71, No 7, p 203 (Nov 1972)
Microstructures, Vol 3, No 4, p 1 7 (June/ July 1972)
An investigation was made o f the strength of c e m e n t paste reinforced with up to 3 vol % o f alumina filaments with diameters between 0-5 and 0-8 ram. This was combined with an investigation of the interface and the b o n d strength between the c e m e n t and the filaments. The UTS and fracture energy were improved by factors o f more t h a n two when the c e m e n t was reinforced with 2"8 vol % o f aligned, c o n t i n u o u s Filaments.
Methods are described for the investigation of the chemical compatibility o f the phases in systems that are used or might be used as fibre-reinforced systems. In particular the reaction products and reaction kinetics at the f i b r e - m a t r i x interface are considered. These can be studied with microanalytical techniques which include optical and electron microscopy, electron probe microanalysis and X-ray diffraction. The techniques were illustrated by descriptions o f specific iovestigations o f the system s, Ti-B and Ti-SiC as well as systems in which the degradation o f SiC whiskers in titanium is inhibited by coating the whiskers with silver, gold or rhodium.
Effect of, aggregate-matrix interaction on mechanical properties of concrete Kosaka, Y., Yanifawa, Y. and Ota, F.
Proc 15th Japan Congress on Materials Research, pp 1 2 8 - 1 3 2 (1972) The effect o f surface condition o f this aggregate on the b o n d strength between it and the mortar matrix and the compressive and tensile strength o f concrete is studied. Cylindrical cast m o r t a r aggregate was used with three surface conditions: (a) as cast, (b) coated with e p o x y resin and fine aggregate and (c) coated with polyethylene. The compressive strength o f concrete with type (a) aggregate increased with aggregate strength, but there was no variation for types (b) and (c). The compressive strength o f the concrete with types (a) and (c)
Contribution to the joining of fibre-' reinforced materials having an aluminium matrix (in German) Nixdorf, J. Aluminium, 1Iol 48, No 8,
p 553 (Aug 1972) Techniques for joining fibre-reinforced materials are surveyed. The possibilities and limits o f each technique for individual cases are described. It is i m p o r t a n t to compensate for weaknesses introduced at joints by rivet or bolt holes. Welding processes should introduce as little heat
91
of dispersion hardening and the effects of fibres on the behaviour o f dislocations in composites are discussed. A technique for the analysis of fracture
strength data for carbon fibres Jones, B. F. and Wilkins, B. J. S.
Longitudinal tensile failure of unidirectional fibrous composites Lifshitz, J. M. and Rotern, A.
Journal o f Materials Science, Vol 7, No 8, pp 861 869 (Aug 1972) A theoretical t r e a t m e n t is described o f the tensile strength o f a unidirectional fibrous composite subjected to a tensile load in the fibre direction. The fibres are assumed to have a statistical strength distribution which results in fibre failure prior to composite failure. The model derived has a failure geometry similar to that observed in tests on glass/epoxy composites.
The production of metal fibres and wires directly from the melt Butler, I. G., Kurry, W., Gillot, J. and Lux, B. Fibre Science and Technology,
Vol 5, No 4, p 243 (Oct 1972) A s u m m a r y o f the basic problem o f the production o f metal fibres directly from low viscosity melts is followed by a mathematical consideration o f the stability of liquid jets in terms o f the drop formation time. The results o f e x p e r i m e n t s on a model water jet system are correlated with this t r e a t m e n t and data concerning the variation in jet break-up length with jet velocity for molten steel and aluminium are presented. Methods o f fibre production from the melt are reviewed as a concluding section, Properties o f filaments sintered from boehmite gels Badker, P. A., Bailey, J. E. and Barker, H. A.
Transactions o f the British Ceramic Society, 1Iol 71. No 7, p 193 (Nov 1972) An investigation was made o f the microstructure and mechanical properties o f filaments ( 0 . 5 - 1 . 0 m m diameter) produced by the extrusion and sintering o f alumina hydrates pastes. The strength of the filaments was high in comparison with other types o f alumina with similar porosity and grain size. Possible explanations for this are discussed in terms o f pore size and distribution as well as of surface conditions. The densification behaviour and microstructural developm e n t of b o e h m i t e gels during sintering were investigated with a view to optimizing the fabrication techniques.
Reinforcement of structural materials by long strong fibres Kelly, A. Metallurgical Transactions,
Fo13, No 9, p 2313 (Sept 1972) The theory o f the reinforcement o f matrices by long discontinuous fibres is presented in detail. The practical implications o f the conclusions o f the analysis are discussed. Those composites in which the fibres are intended to stiffen a relatively ductile matrix, and those in which the fibres are intended to inhibit the propagation of cracks in relatively brittle matrices, are considered. The m e c h a n i s m s o f fibre reinforcement are compared with those
COMPOSITES, MARCH 1973
Fibre Science and Technology, Fol 5, No 4, p 315 (Oct 1972) It is suggested that the disadvantage o f histograms in the examination of the distribution of fibre fracture strength data, namely that very small groups m u s t be plotted to separate m o d e s which are close together, m a y be overcome by plotting derived data. It is s h o w n that when the measured fracture strength values are ranked and plotted against cumulative probability o f failure the distribution o f values can be compared with a standard unimodal distribution and any deviations from this will be revealed in one plot. This technique is being used to examine the effects of fast n e u t r o n irradiation on fibre strength.
Transverse tensile properties of an unbonded model composite Butcher, B. R. Journal o f Materials Science, Fol 7, No 8, pp 8 7 7 - 8 8 7 (Aug 1972) Unbonded model composites of steel rods in aluminium and aluminium with holes of identical geometry have been tested in tension. The c o m p l e x behaviour of Young's m o d u l u s , stress at the elastic limit and UTS have been measured and applied to real composite materials.
CERA MIC MA TRICES
aggregate was n o t very different from a concrete with voids in place o f aggregate. Formulas for estimating the compressive strength of polymer-modified mortars Amoaha, Y. Proc o f the 15th Japan
Congress on Material Research. pp 1 5 1 - 1 5 3 (1972) A "binder-void" ratio a = (V..c + V_)(V~ p u + Vw) is defined when Ve = volume of cement, lip = volume of polymer, Va = volume of air and V w = volume of water. The variation of compression strength with l / a for for various polymer modified mortars was determined experimentally. With certain exceptions the formula A log F = - - - + C Bl/a was found to apply, where F = compressive strength, A, B and C are constant.
The theoretical prediction of the cracking
stress of glass fibre reinforced inorganic cement Chan, H. C. and Patterson, W. A. Journal
o f Materials Science, Vol 7, No 8, pp 8 5 0 - 8 6 0 (Aug 1972) The cracking stress for glass fibre reinforced cement is predicted from fracture mechanics calculations and experiments appear to verify those predictions. The onset o f cracking can be increasingly suppressed with decreasing inter-fibre spacing in this type o f material.
METAL MA TRICES Chemical compatibility in metal-fiber
composites
Alumina filament reinforced cement paste Standhammer, K. P., Murr, L. E., Bailey, J. E., Barker, H. A. and Urbanowicz, C. Marinoff, C. and Reineking,V.
Transactions o f the British Ceramic Society, Fol 71, No 7, p 203 (Nov 1972)
Microstructures, Vol 3, No 4, p 1 7 (June/ July 1972)
An investigation was made o f the strength of c e m e n t paste reinforced with up to 3 vol % o f alumina filaments with diameters between 0-5 and 0-8 ram. This was combined with an investigation of the interface and the b o n d strength between the c e m e n t and the filaments. The UTS and fracture energy were improved by factors o f more t h a n two when the c e m e n t was reinforced with 2"8 vol % o f aligned, c o n t i n u o u s Filaments.
Methods are described for the investigation of the chemical compatibility o f the phases in systems that are used or might be used as fibre-reinforced systems. In particular the reaction products and reaction kinetics at the f i b r e - m a t r i x interface are considered. These can be studied with microanalytical techniques which include optical and electron microscopy, electron probe microanalysis and X-ray diffraction. The techniques were illustrated by descriptions o f specific iovestigations o f the system s, Ti-B and Ti-SiC as well as systems in which the degradation o f SiC whiskers in titanium is inhibited by coating the whiskers with silver, gold or rhodium.
Effect of, aggregate-matrix interaction on mechanical properties of concrete Kosaka, Y., Yanifawa, Y. and Ota, F.
Proc 15th Japan Congress on Materials Research, pp 1 2 8 - 1 3 2 (1972) The effect o f surface condition o f this aggregate on the b o n d strength between it and the mortar matrix and the compressive and tensile strength o f concrete is studied. Cylindrical cast m o r t a r aggregate was used with three surface conditions: (a) as cast, (b) coated with e p o x y resin and fine aggregate and (c) coated with polyethylene. The compressive strength o f concrete with type (a) aggregate increased with aggregate strength, but there was no variation for types (b) and (c). The compressive strength o f the concrete with types (a) and (c)
Contribution to the joining of fibre-' reinforced materials having an aluminium matrix (in German) Nixdorf, J. Aluminium, 1Iol 48, No 8,
p 553 (Aug 1972) Techniques for joining fibre-reinforced materials are surveyed. The possibilities and limits o f each technique for individual cases are described. It is i m p o r t a n t to compensate for weaknesses introduced at joints by rivet or bolt holes. Welding processes should introduce as little heat
91