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Filamentary sapphire: characterization. Part 1: Growth and microstructural. Part 2: Fracture strength in tension
Silicon nitride products Arrol, W. J. (Joseph Lucas Industries Ltd) UK Pat 1 280 459 (5 Jul 1972) A process is described for flamc spraying silicon and spraying inert fibrous material onto a mandrel and then heating these in an atmosphere of nitrogen.
in an a q u e o u s bath containing (a) ions of Cu, Zn Mn, Cr, V, Fe, Co, Ni and (b) hydroxylamine at 6 0 - 1 3 0 ° C , followed by oxidizing the treated fibres in an oxygencontaining atmosphere and then carbonizing them under inert or reducing conditions.
New m e t h o d s of producing carbon fibres with a high m o d u l u s of elasticity (Le Carbone-Lorraine) UK Pat 1 2b¢0 850 (5 Jul 1972) Polyacrylonitrile polymer of c o p o l y m e r (85'2; acrylonitrile units) is treated with one or more halogen-frec cthylenically unsaturated copolymerizable m o n o m e r s ,
Reinforced plastics shell structure Meyer, L. S. (McCreary Industrial Products Co) UK Pat 1 280 852 (5 Jul 1972) A shell structure is m o u n t e d on a shaft consisting o f two spaced discs and fabricated from laminated layers of plastic and reinforcing material: each disc has a hub
Abstracts of journals Compiled by Dr H. A. Barker, I. Bell, B. Gill and R. Warren, Department of Metallurgy and Materials Technology, University of Surrey, Guildford, England GENERA L A comparative study of tensile fracture mechanisms Mullin, J. V. and Mazzio, V. F. Journal o f Composite Materials, Vol 6 pp 267¢- 27h (Apr 1972) A series o f tests was carried out to identify the failure m e c h a n i s m s for some of the more widely-used carbon fibres in an epoxy matrix under tensile loading. Results and micrographs show conditions under which catastrophic failure or debonding failure predominate
Filamentary sapphire: characterization. Part 1 : Growth and microstructural. Part 2: Fracture strength in tension Pollock, J. T. A. Journal o f Materials Science, Vol 7, No 6, pp 631 65.¢ (Jun 1972) An experimental study is describcd of the c o n t i n u o u s melt growth o f filamentary c-axis sapphire having a nominal 0.025 cm diameter. A range o f growth rates from 2-5 to 7.5 c m / m i n were studied using thc 'edge-defined, film-fed growth' technique. Part 1 o f this two-part paper deals with aspects of filamentary growth and its effect on the primary structural characteristic of the filamcnt, which is found to bc the presence of voids arranged in specific patterns. Part 2 e x a m i n e s the tensile strength o f these filaments which appears to he a decreasing function of filament diameter. Using a melttemperature controlling device, filaments could be grown whose strength was independent o f growth rate and found to bc about 2.75 G N / m 2. Filamentary sapphire. Part 3: The growth of void-free sapphire filament at rates up to 3-0 c m / m i n . Pollock, J. T. A. Journal o f Materials Science, 1~)1 7, No 7. pp 787 792 (Jttl 197~)
COMPOSITES . JANUARY
1973
[!sing tim 'edge-defined, fihn-fcd' growth technique described in Part 1 but with a tungsten, instead of m o l y b d e n u m , orifice, it is possible to grow filamentary sapphire at rates up to 3.0 c m / m i n entirely free of microvoids. The filaments act as light pipes and have an average tensile strength of 3.3 G N ' m 2. The rolc of tungsten in creating the planar solid/ liquid growth interface necessary for voidfree growth was investigated and the essential conditions are discussed in terms of thermal generation and heat transfer processes occurring within the liquid film from which the crystal is drax~n. Tbe fracture energy of a glass fibre composite Beaumont, P. W. R. and Phillips, D. ('. .lonrnal o.['Materials Science, 1"ol 7, No h, pp 6,q2 686 (Jun 1972) A comparison of the works of fracture observed from bending o f a n o t c h e d beam specimen and the linear elastic fracture mechanics analysis of an edge-notched tensile plate specimen shows that the lbrmer is always greater and s h o ~ s a strain-rate dependence which is abscnl in the latter. It is postulated that the smallcr value is a measure of debonding energy while the layer is made up from debonding and fibre pull-out energies. Future of composites rests on adequate control I.'.llis, P. Textile Manu.facturer. l'ol 9% No 1169, p .¢0 (Jtd 1972) A recent confcrcncc at the University of Bradford in the School o f Textiles is reported. The underlying theme was that better control o f the laminated and composite textile industry could only bc achieved by integration o f these activitics into the textile industry as a whole. The glass fiber and glass laminate industry in the sixth five-year plan Shciko, V. E. and Kydryashoua, V. N. (;lass and Ceramics. Vol 2& No 9, p 521 (Sep 197I)
and rim and at least some layers enter into these. The structure is further comprised o f a reinforced plastics sllcll extending between the rims and fixed to the disc rims. Reinforced thermoplastics material Wicker, G. L. (Turner Brothers Asbestos Co Ltd) UK Pat 1 281 089 (12 Jul 1972) Polypropylene or copolymcrs o f propylcnc are filled with particulate or fibrous mineral silicates, the surface presenting largely siloxane units tree of chrysotilc fibres. These composites are stabilized by c o m p o u n d i n g with selected phenolic and amine antioxidants.
The glass fibre and laminate industry in the Soviet Union is reviewed for the last q u i n q u e n n i u m . The production or fibre and laminates have increased during this period by 272 and 3 times respectively, making the Soviet Union the second largest glass fibre producer in the world. A standard glass composition with only 0-5'7, alkali content is used, assisting in the production of high quality goods for electrical insulation. Other innovations include a staple glass o f 0-5 ,am diameter, glass-filled thermoplastics, glass laminate pipes and glass cord for automobile tyres. Impurity effects in carbon fibres Liberman, M. L. and Noles. Journal o f Materials Science, I/ol 7. No 6, pp 054 -662 (Jun 1972) Outgassing experiments have been performed on a variety of PAN- and Rayonbased carbon yarns. Major residual impurities, as well as those introduced from surface treatments, have been identified. Sulphur has been shown to be a major c o n t a m i n a n t for Rayon-based materials and removal o f this element as a volatile c o m m e n c e s at around 1 3 0 0 ' C . It has been found that decreases in interlayerspacing and fibre tensile strength are associated with this sulphur evolution, whereas apparent crystallitc size and Young's m o d u l u s arc unaffected.
C E R A M I C MA TRICES Carbon fibre composites with ceramic and glass matrices. Part 1 : Discontinuous fibres. Part 2: Continuous fibres. Sambell, R. A, J., Bowcn, D. 1t., Phillips, D. C. and Briggs, A. Journal o.tMaterials Science, Vol 7. No 6, pp 663 6SI (Jtm 1972) A study of the fabrication, microstructure and some o f the mechanical and thermal properties o f a variety of glass matrices incorporating continuous and discontinuous high m o d u l u s carbon fibres and discontinuous zirconia fibres. Where fibres were aligned, dramatic increases in fracture stress of the composites over the matrix values wcre observed: this was coupled with an increase in the observed work of fracture. These results are discussed in terms of fibre volume traction, mismatch of thermal coefficients between matrix and fibre and the nature of the interface.
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in an a q u e o u s bath containing (a) ions of Cu, Zn Mn, Cr, V, Fe, Co, Ni and (b) hydroxylamine at 6 0 - 1 3 0 ° C , followed by oxidizing the treated fibres in an oxygencontaining atmosphere and then carbonizing them under inert or reducing conditions.
New m e t h o d s of producing carbon fibres with a high m o d u l u s of elasticity (Le Carbone-Lorraine) UK Pat 1 2b¢0 850 (5 Jul 1972) Polyacrylonitrile polymer of c o p o l y m e r (85'2; acrylonitrile units) is treated with one or more halogen-frec cthylenically unsaturated copolymerizable m o n o m e r s ,
Reinforced plastics shell structure Meyer, L. S. (McCreary Industrial Products Co) UK Pat 1 280 852 (5 Jul 1972) A shell structure is m o u n t e d on a shaft consisting o f two spaced discs and fabricated from laminated layers of plastic and reinforcing material: each disc has a hub
Abstracts of journals Compiled by Dr H. A. Barker, I. Bell, B. Gill and R. Warren, Department of Metallurgy and Materials Technology, University of Surrey, Guildford, England GENERA L A comparative study of tensile fracture mechanisms Mullin, J. V. and Mazzio, V. F. Journal o f Composite Materials, Vol 6 pp 267¢- 27h (Apr 1972) A series o f tests was carried out to identify the failure m e c h a n i s m s for some of the more widely-used carbon fibres in an epoxy matrix under tensile loading. Results and micrographs show conditions under which catastrophic failure or debonding failure predominate
Filamentary sapphire: characterization. Part 1 : Growth and microstructural. Part 2: Fracture strength in tension Pollock, J. T. A. Journal o f Materials Science, Vol 7, No 6, pp 631 65.¢ (Jun 1972) An experimental study is describcd of the c o n t i n u o u s melt growth o f filamentary c-axis sapphire having a nominal 0.025 cm diameter. A range o f growth rates from 2-5 to 7.5 c m / m i n were studied using thc 'edge-defined, film-fed growth' technique. Part 1 o f this two-part paper deals with aspects of filamentary growth and its effect on the primary structural characteristic of the filamcnt, which is found to bc the presence of voids arranged in specific patterns. Part 2 e x a m i n e s the tensile strength o f these filaments which appears to he a decreasing function of filament diameter. Using a melttemperature controlling device, filaments could be grown whose strength was independent o f growth rate and found to bc about 2.75 G N / m 2. Filamentary sapphire. Part 3: The growth of void-free sapphire filament at rates up to 3-0 c m / m i n . Pollock, J. T. A. Journal o f Materials Science, 1~)1 7, No 7. pp 787 792 (Jttl 197~)
COMPOSITES . JANUARY
1973
[!sing tim 'edge-defined, fihn-fcd' growth technique described in Part 1 but with a tungsten, instead of m o l y b d e n u m , orifice, it is possible to grow filamentary sapphire at rates up to 3.0 c m / m i n entirely free of microvoids. The filaments act as light pipes and have an average tensile strength of 3.3 G N ' m 2. The rolc of tungsten in creating the planar solid/ liquid growth interface necessary for voidfree growth was investigated and the essential conditions are discussed in terms of thermal generation and heat transfer processes occurring within the liquid film from which the crystal is drax~n. Tbe fracture energy of a glass fibre composite Beaumont, P. W. R. and Phillips, D. ('. .lonrnal o.['Materials Science, 1"ol 7, No h, pp 6,q2 686 (Jun 1972) A comparison of the works of fracture observed from bending o f a n o t c h e d beam specimen and the linear elastic fracture mechanics analysis of an edge-notched tensile plate specimen shows that the lbrmer is always greater and s h o ~ s a strain-rate dependence which is abscnl in the latter. It is postulated that the smallcr value is a measure of debonding energy while the layer is made up from debonding and fibre pull-out energies. Future of composites rests on adequate control I.'.llis, P. Textile Manu.facturer. l'ol 9% No 1169, p .¢0 (Jtd 1972) A recent confcrcncc at the University of Bradford in the School o f Textiles is reported. The underlying theme was that better control o f the laminated and composite textile industry could only bc achieved by integration o f these activitics into the textile industry as a whole. The glass fiber and glass laminate industry in the sixth five-year plan Shciko, V. E. and Kydryashoua, V. N. (;lass and Ceramics. Vol 2& No 9, p 521 (Sep 197I)
and rim and at least some layers enter into these. The structure is further comprised o f a reinforced plastics sllcll extending between the rims and fixed to the disc rims. Reinforced thermoplastics material Wicker, G. L. (Turner Brothers Asbestos Co Ltd) UK Pat 1 281 089 (12 Jul 1972) Polypropylene or copolymcrs o f propylcnc are filled with particulate or fibrous mineral silicates, the surface presenting largely siloxane units tree of chrysotilc fibres. These composites are stabilized by c o m p o u n d i n g with selected phenolic and amine antioxidants.
The glass fibre and laminate industry in the Soviet Union is reviewed for the last q u i n q u e n n i u m . The production or fibre and laminates have increased during this period by 272 and 3 times respectively, making the Soviet Union the second largest glass fibre producer in the world. A standard glass composition with only 0-5'7, alkali content is used, assisting in the production of high quality goods for electrical insulation. Other innovations include a staple glass o f 0-5 ,am diameter, glass-filled thermoplastics, glass laminate pipes and glass cord for automobile tyres. Impurity effects in carbon fibres Liberman, M. L. and Noles. Journal o f Materials Science, I/ol 7. No 6, pp 054 -662 (Jun 1972) Outgassing experiments have been performed on a variety of PAN- and Rayonbased carbon yarns. Major residual impurities, as well as those introduced from surface treatments, have been identified. Sulphur has been shown to be a major c o n t a m i n a n t for Rayon-based materials and removal o f this element as a volatile c o m m e n c e s at around 1 3 0 0 ' C . It has been found that decreases in interlayerspacing and fibre tensile strength are associated with this sulphur evolution, whereas apparent crystallitc size and Young's m o d u l u s arc unaffected.
C E R A M I C MA TRICES Carbon fibre composites with ceramic and glass matrices. Part 1 : Discontinuous fibres. Part 2: Continuous fibres. Sambell, R. A, J., Bowcn, D. 1t., Phillips, D. C. and Briggs, A. Journal o.tMaterials Science, Vol 7. No 6, pp 663 6SI (Jtm 1972) A study of the fabrication, microstructure and some o f the mechanical and thermal properties o f a variety of glass matrices incorporating continuous and discontinuous high m o d u l u s carbon fibres and discontinuous zirconia fibres. Where fibres were aligned, dramatic increases in fracture stress of the composites over the matrix values wcre observed: this was coupled with an increase in the observed work of fracture. These results are discussed in terms of fibre volume traction, mismatch of thermal coefficients between matrix and fibre and the nature of the interface.
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