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Carbon fibres: their selection and manufacture
Process for the preparation of carbon fibers (Nippon Carbon Co Ltd) UK Patent
Specification, 1,222,881 (17 February 1971) Carbon fibres are prepared from cellulosic, polyvinyl alcoholic and acrylic fibres. The fibrous material is treated under tension by heating in an atmosphere containing hydrochloric acid vapour, giving higher tensile strength and modulus of elasticity. Examples and details are given for the three major groups of precursor fibres. Temperature ranges of heat treatment are given for each of the two-step process.
Composite material: glass-ceramic matrix composite Hayward, A. P. St. J. (Rolls-Royce Ltd) UK Patent Specification,
Manufacture of carbon and graphite filament and yarn (Great Lakes Carbon Corp) UK Patent
1,223,193 (24 February 1971)
Specification, 1,223,380 (24 February 1971)
Carbon, graphite, boron or silicon carbide filaments are incorporated in a glass-ceramic matrix, parallel to one another. Metal oxides can be added to the matrix to modify the glass. Matrix material and filament are selected on having the same coefficient of thermal expansion. The composite is formed at high temperature and pressure, and has a density less than that of aluminium and its alloys.
Continuous lengths of polyacrylonitrile filament are stretched in steam to 150% of their initial length. Heat treatment in an oxidizing atmosphere is followed by heat treatment under tension. Carbonizing of the filaments is carried out above 700°C. Minimum lengths are at least 2000 ft to enable conventional textile handling to be used and also to produce a filament suitable for filament winding.
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 Copies o f original articles are best obtained by writing directly to the journal in which they appeared. The addresses o f journals can be found in 'World list o f scientific periodicals', 'Willings press guide', 'Newspaper press directory' and for American journals only, 'N. 14/.A yer's directory o f newspapers and periodicals'.
G ENERA L Analysis of the rail shear test applications and limitations Whitney, J. M., Stansbarger, D. L. and Howell, H. B. Journal of Composite
Materials, Vol 5, pp 24 - 34 (January 1971) A detailed theoretical and experimental analysis of the rail shear test is presented. A Fourier Series solution is obtained for the stresses in an idealized rail shear specimen. Fibrereinforced rubber is used to verify qualitatively the theoretical results, and rail shear strength and modulus data for high modulus composites are compared with values predicted from lamination theory. Results show, with some limitations, that this test can be useful in the determination of in-plane shear properties of a laminated composite. (71 / 1/24)
Behaviour of single wood fibres under axial tensile stress Page, D. H., E1-Husseiny, F. and Winkler, K. Nature, Vo1229, No 5282,
pp 252 - 253 {January 1971) To provide for simultaneous microscopical examination and tensile testing of single wood fibres about 1 mm long and 30~m in diameter, an apparatus consisting of an Instron tensile
testing machine and a Zeiss microscope was built. The most striking observation is that the fibre undergoes an apparent twisting deformation when loaded axially with its ends rigidly held. This is explained in terms of a model of the fibre as a helically wound fibre reinforced tube. Technologically the results appear to be applicable to loosely bonded wood fibre products such as non-woven fabrics, but not to structures such as paper and board. (71/1/25)
Calculation of the elastic moduli of binary composites Wang, F. F. V. Materials Science and Engineering, Vol 7, No 2, p 103,
(1970) The introduction of a normal distribution to the approach of Hashin and Shtrikman's variational analysis of the elastic moduli of binary composites was made. It is claimed to be a valid improvement in the analysis of the moduli of systems with up to 50% of the second phase. The basic assumption is that there is a typical reference cube of material in the body upon which rigorous stress and strain boundary conditions may be imposed. From these the bounds of the elastic constants may be found and extrapolated to the whole body. (7111126)
Carbon fibres: their selection and manufacture Clarke, A. J. Design Engineering, pp
111 - 115 {February 1971) A fairly detailed description, meaningful to the layman, is given of the process of manufacture of both high strength and high modulus carbon fibres. This includes the spinning of the precursor fibre, its structure and properties, followed by all the stage of conversion to carbon fibre together with the chemical reactions occurring. The effect of fibre structure on strength and modulus is shown and described. (71 / 1/27)
Cross sectioning techniques for scanning electron microscopy Felton, C. D. Journal of Materials
Science, Vol 6, No I, pp 89 (January 1971)
92
A description is given, with illustrations, of the classical paraffin method of specimen mounting. This technique is well-known in the study of textiles and is here applied to a variety of fibres prior to sectioning in a microtome and examination in the SEM. It is claimed that this process eliminates the need for microtoming skill and produces a sample that can be viewed from all sides and angles. (71/1/28)
COMPOSITESJune 1971
123
Specification, 1,222,881 (17 February 1971) Carbon fibres are prepared from cellulosic, polyvinyl alcoholic and acrylic fibres. The fibrous material is treated under tension by heating in an atmosphere containing hydrochloric acid vapour, giving higher tensile strength and modulus of elasticity. Examples and details are given for the three major groups of precursor fibres. Temperature ranges of heat treatment are given for each of the two-step process.
Composite material: glass-ceramic matrix composite Hayward, A. P. St. J. (Rolls-Royce Ltd) UK Patent Specification,
Manufacture of carbon and graphite filament and yarn (Great Lakes Carbon Corp) UK Patent
1,223,193 (24 February 1971)
Specification, 1,223,380 (24 February 1971)
Carbon, graphite, boron or silicon carbide filaments are incorporated in a glass-ceramic matrix, parallel to one another. Metal oxides can be added to the matrix to modify the glass. Matrix material and filament are selected on having the same coefficient of thermal expansion. The composite is formed at high temperature and pressure, and has a density less than that of aluminium and its alloys.
Continuous lengths of polyacrylonitrile filament are stretched in steam to 150% of their initial length. Heat treatment in an oxidizing atmosphere is followed by heat treatment under tension. Carbonizing of the filaments is carried out above 700°C. Minimum lengths are at least 2000 ft to enable conventional textile handling to be used and also to produce a filament suitable for filament winding.
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 Copies o f original articles are best obtained by writing directly to the journal in which they appeared. The addresses o f journals can be found in 'World list o f scientific periodicals', 'Willings press guide', 'Newspaper press directory' and for American journals only, 'N. 14/.A yer's directory o f newspapers and periodicals'.
G ENERA L Analysis of the rail shear test applications and limitations Whitney, J. M., Stansbarger, D. L. and Howell, H. B. Journal of Composite
Materials, Vol 5, pp 24 - 34 (January 1971) A detailed theoretical and experimental analysis of the rail shear test is presented. A Fourier Series solution is obtained for the stresses in an idealized rail shear specimen. Fibrereinforced rubber is used to verify qualitatively the theoretical results, and rail shear strength and modulus data for high modulus composites are compared with values predicted from lamination theory. Results show, with some limitations, that this test can be useful in the determination of in-plane shear properties of a laminated composite. (71 / 1/24)
Behaviour of single wood fibres under axial tensile stress Page, D. H., E1-Husseiny, F. and Winkler, K. Nature, Vo1229, No 5282,
pp 252 - 253 {January 1971) To provide for simultaneous microscopical examination and tensile testing of single wood fibres about 1 mm long and 30~m in diameter, an apparatus consisting of an Instron tensile
testing machine and a Zeiss microscope was built. The most striking observation is that the fibre undergoes an apparent twisting deformation when loaded axially with its ends rigidly held. This is explained in terms of a model of the fibre as a helically wound fibre reinforced tube. Technologically the results appear to be applicable to loosely bonded wood fibre products such as non-woven fabrics, but not to structures such as paper and board. (71/1/25)
Calculation of the elastic moduli of binary composites Wang, F. F. V. Materials Science and Engineering, Vol 7, No 2, p 103,
(1970) The introduction of a normal distribution to the approach of Hashin and Shtrikman's variational analysis of the elastic moduli of binary composites was made. It is claimed to be a valid improvement in the analysis of the moduli of systems with up to 50% of the second phase. The basic assumption is that there is a typical reference cube of material in the body upon which rigorous stress and strain boundary conditions may be imposed. From these the bounds of the elastic constants may be found and extrapolated to the whole body. (7111126)
Carbon fibres: their selection and manufacture Clarke, A. J. Design Engineering, pp
111 - 115 {February 1971) A fairly detailed description, meaningful to the layman, is given of the process of manufacture of both high strength and high modulus carbon fibres. This includes the spinning of the precursor fibre, its structure and properties, followed by all the stage of conversion to carbon fibre together with the chemical reactions occurring. The effect of fibre structure on strength and modulus is shown and described. (71 / 1/27)
Cross sectioning techniques for scanning electron microscopy Felton, C. D. Journal of Materials
Science, Vol 6, No I, pp 89 (January 1971)
92
A description is given, with illustrations, of the classical paraffin method of specimen mounting. This technique is well-known in the study of textiles and is here applied to a variety of fibres prior to sectioning in a microtome and examination in the SEM. It is claimed that this process eliminates the need for microtoming skill and produces a sample that can be viewed from all sides and angles. (71/1/28)
COMPOSITESJune 1971
123