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Bending of multi-layered belts
filaments in a copper matrix have been prepared by casting and cold working. Cold rolling or drawing causes the precipitated 10/am Nb particles in the cast alloy to be elongated and aligned, forming quasi-continuous superconducting paths. Addition of a small amount of aluminium to the alloy improves continuity of the filaments. The wire appears to have good superconducting properties and is not damaged by repeated bending for example.
hardening. At a later stage apparent softening occurred due to the formation of cracks. The fatigue life of the composite was greater than that of the ascast alloy over the entire temperature range. This superiority increased with decreasing strain amplitude and could be explained in terms of the deflection of cracks by the Cr-rich lamellae.
case were entrapped by the solid fraction of the alloy for sufficient time to allow wetting interactions to take place. In this way composites with up to 30weight% of A1203 or SiC were successfully prepared and die-cast. Some of the heated composites were thixotropic, ie they could be handled as a solid but exhibited fluid behaviour during diecasting.
Microstructure and growth kinetics of the fibrous composite subscale formed by internal oxidation of SmCo 5 Bartlett, R. W. and Jorgensen, P. J. Metallurgical Transactions, Vol 5, No 2 [Feb 1974)pp 355-361 A study was made of the oxidation kinetics of SmCo5 between 100 and 1125°C. During oxidation a composite subscale grows that consists of Sm203 fibres in a matrix of cobalt with fibres generally perpendicula to the subscaleintermetallic interface. The fibre size increased with oxidation temperature above 750°C. The growth of the scale follows a parabolic oxidation law. The high rates of growth suggest that it occurs by oxygen diffusion down the cobalt/oxide interfaces.
The present position of the development of aluminium reinforced with carbon fibres The tensile failure modes of metallgnatowitz, E. Aluminium, 11o150, matrix composite materials No 5 (May 1974) p 334 [supplement in Wright, M. A. and Wills, J. L. Journal English, p 17) of the Mechanics and Physics of Solids, Carbon fibre-reinforced aluminium Vo122, No 3 (May 1974) pp 161-176 should be suitable for use up to 500°C The strengths of individual boron fibres making it, for instance, an attractive extracted from various as-received and material for parts of the skin of superthermally-fatigued aluminium alloy conic aircraft which reach 550°C at matrix materials were measured. The Mach 4. After initially disappointing results are described in terms of a tests the theoretically calculated strengths Weibull distribution and strengths of are now being attained by pre-casting the composites made from these fibres are fibres or by chemical surface treatment. calculated in terms of lower and upper Problems associated with shaping, joint- bounds. Tests conducted on composite ing, corrosion etc still have to be solved, specimens indicate that strengths but broadly based use of such materials approaching the upper bounds can be still depends very much on the cost of the achieved in composites fabricated by raw materials and manufacturing processes, normal diffusion bonding techniques. Cyclic temperature changes effectively Strengths and failure mechanisms of a reduced the strength values towards the Co-15Cr-I 3 TaC directionally solidified lower bounds, and it is concluded that eutectic alloy this effect resulted fro~ the degradation Buchanan, E. R. and Tarshis, L. A. of the strength of the fibre/matrix bond. Metallurgical Transactions, Vol 5, No 6 [Jun 1974)pp 1413-1422 Transient stress states in composite A study was made of the tensile and creep stress/rupture properties of a Co-Cr-TaC Garmong, G. Metallurgical Transactions, aligned eutectic consisting of fibres of Vol 5, No 5 (May 1974) pp 1257-1258 TaC in a Co-Cr solid solution matrix. If the isothermal creep equations for Comparison with the tensile properties the individual components of a composof the pure matrix indicated that the iter are of a different form, then the fibres bear 80-90% of a tensile load on distribution of stress between the comthe composite. The tensile breaking ponents can be expected to change with strength of the fibres was calculated at time during the creep of the composite. 5700 MN/m 2 at room temperature, fall- This effect is analyzed theoretically and ing to 2000 MN/m 2 at 1235°C. The predictions of the stress redistribution stress-rupture properties of the composite made for metal matrix composites. at low stresses (-~ 140 MN/m 2) were superior to those of superalloys but were RESIN MA TRICES inferior at higher stress levels (-~ 350 MN/m2). This was found to be due to Bending of multi-layered belts a change in the rupture mechanism of Tabaddor, F. Fibre Science and the composite. At low stresses and high Technology, Vol 7, No 2 [Apr 1974) temperature the failure is thought to p 89 depend on matrix failure whereas at high The bending of multi-layered belts of stresses and lower temperatures fracture thin, stiff plies bonded with soft rubber is considered to originate in the fibres. plies is analysed mathematically and the analysis technique is applied to obtain Superconductivity composite of copper the bending stresses in a sandwich belt and niobium - a metallurgical approach as it bends round a pulley. The results Tsuei, C. C. J App Physics, Vo145, are compared with those obtained from No 3 [March 1974)p 1385 beam theory and the strain values preSuperconducting composites of niobium dicted are shown to be lower. It is noted
Novel morphology of Pb/Sn/Cd/Zn quaternary euteetic Fisher, D. J. and Kurz, W. Metallurgical Transactions, Vol 5, No 6 [June 19 74) pp 1508-1510 The quaternary eutectic, Pb, Sn, Cd, Zn, (28.6, 52.45, 16.7 and 2.25 weight % respectively) was grown directionally at between 0.05 and 2cm/h with a temperature gradient of 23°C/cm. The resulting microstructure consisted of aligned lamellae of Cd sandwiched between lamellae of Pb in a tin-rich matrix. Lamellae of Zn had grown at right angles to the Cd and Pb lamellae, so producing a 'lattice-work' appearance. Preparation and casting of metalparticulate non metal composites Mehrabian, R., Rick, R. G. and Flemings, M. C. Metallurgical Transactions, Vo15, No 6 [June 1974) pp 1899-1905 A method was developed for the preparation of composites of non-metallic particles dispersed in an alloy matrix. The composites were produced in a partly liquid state and so were suitable for casting and die-casting. The process consisted of vigorously mixing the particles, (A1203, SiC or glass) into a partially-molten alloy (A1/5 weight % St/ 2weight% Fe). The particles, which are initially not wetted by the liquid alloy, would normally segregate but in this
140
COMPOSITES. MAY 1975
that the shear strains in these belts are not considered in the beam theory.
Charpy impact characteristics of fiberglass reinforced plastics with an instrumented machine Hojo, H. et al. Proc of l 7th Japan Congress on Materials Research (Kyoto 1974)p 167 The impact energy of glass-reinforced polyester at low and high temperatures has been studied using a Charpy impact tester. Various fibre configurations were used ranging from unidirectional to random mat. Strain gauges were mounted on each side of the hammer and observations were made using a synchroscope. It is suggested that the load/time curve is important as well as the total energy absorption in studying frp materials.
Effects of watery environment on fatigue strength of frp Masuda, Y. Proc of17th Japan Congress on Materials Research (Kyoto 1974)p 172 The static and fatigue strength of frp consisting of glass cloth and polyester resin has been measured in tension, compression and bending, after immersion in plain and sea water. Saturation with plain or sea water was observed to occur after 4 0 - 1 0 0 days depending on
laminate thickness. There was a decrease of flexural and compressive strength in proportion to the water absorption, the final level being about 70-80% of its initial value. Little change in tensile strength due to water absorption was observed. The fatigue strength at 106 cycles was reduced to about 60% when saturated with water. No difference between plain and sea water was noticed.
On the study of indigenous natural fibre composites
Anon. Materials Engineering, Vol 78, No 6 (November 19 73) p 36 The materials, construction, applications and costs of honeycomb structures are reviewed with sections on facing materials, core materials and geometry, bonding and properties. Among the non-structural applications of honeycomb structures are as impact energy absorbers for rapidly decelerating objects, as radio frequency shields and as matrices for ablative materials and catalysts.
Paramasivam, T. and Abdul Kalam,
P. J. Fibre Science and Technology, Vol 7, No 2 (Apr 19 74) p 85 The application of natural fibres such as sisal, coconut and jute as reinforcements for low cost epoxy resin based composites has been studied. It is concluded that, since the densities of these fibres are about half of those of glass, the specific properties of these composites are sufficiently high to warrant further evaluation.
STRUCTURES
Honeycomb structures maintain strength while cutting weight
New type of continuous composite steel and concrete bridge Fried, A. Acier-Stahl-Steel, Vo139, No 11 (Nov 1974J p 482-481 A new type of continuous composite steel and concrete bridge has been developed in the Bridge Section of the Department of Main Roads, New South Wales, Australia. In this type of bridge simple supported steel beams are connected without field riveting, bolting or welding in such a way that full continuity and composite action of concrete deck slab and steel beams is achieved. Ease of erection and weight saving in steel beams and consequently greater economy and the feasibility of longer spans are made possible in composite steel and concrete bridges.
Abstracts of patents UK PA TEN TS
Method for forming refractory fibres (Arthur D. Little lnc) UK Pat 1 362 429 (7Aug 1974J Fibres suitable for metal reinforcement are made from materials (which cannot conveniently be melted in a crucible) by continuously feeding a rod into a heating zone, where the material melts and a fibre can be drawn from it. The radius of the rod does not exceed 6.7 times that of the fibre and the length of the molten zone is less than 5.7 times the fibre radius.
Reinforced plastic materials
Laminated materials
(Morganite Modmor Limited) UK Pat
(Lion Fat and Oil Company Limited)
1 362 531 (7Aug 1974) A rod is made by wrapping layers of resin impregnated glass cloth round a mandrel with carbon fibres disposed between the layers. The nature, length, or concentration of the fibres may vary from one part of the rod to another to give different physical properties.
UK Pat 1 362 835 (7Aug 1974) A constructional laminate is made from layers of thermoplastic resin sheets containing calcium sulphite and/or gypsum. The sheets are anisotropic as a result of being orientated in a single direction before laminating.
High inorganic filler content
Filled film product and process
Electrodeposited composite coatings of metal and graphite fluoride (C. Uyemura and Co Ltd) UKPat 1 362 558 (7Aug 1974)
(E. I. Dupont de Nemours and Company) UK Pat I 362 457 (7Aug 1974} A packaging film is made by blending an a-mono-olefine polymer with 26 to 50% by weight of a particulate f'fller. preferably a clay, forming a film which is biaxially stretched until it has a void content of at least 30%.
A self-lubricating surface is produced by making a dispersion of graphite fluoride powder, with a particle size less than 10 ~tm in a metal plating bath containing a water soluble surfactant having a fluorine/carbon bond in the molecule and electrodepositing the metal and powder simultaneously.
High impact and tensile strength materials are made by mixing an ethylene/ propylene copolymer, particularly if a block copolymer, having an ethylene content of 0.1 to 30% with at least 30% of an inorganic filler, excluding mica, having a particle size of 20 #m or less.
COMPOSITES. M A Y 1975
composition (Mitsubishi Petrochemical Co. Ltd)
UK Pat 1 362 912 (7Aug 1974J
141
hardening. At a later stage apparent softening occurred due to the formation of cracks. The fatigue life of the composite was greater than that of the ascast alloy over the entire temperature range. This superiority increased with decreasing strain amplitude and could be explained in terms of the deflection of cracks by the Cr-rich lamellae.
case were entrapped by the solid fraction of the alloy for sufficient time to allow wetting interactions to take place. In this way composites with up to 30weight% of A1203 or SiC were successfully prepared and die-cast. Some of the heated composites were thixotropic, ie they could be handled as a solid but exhibited fluid behaviour during diecasting.
Microstructure and growth kinetics of the fibrous composite subscale formed by internal oxidation of SmCo 5 Bartlett, R. W. and Jorgensen, P. J. Metallurgical Transactions, Vol 5, No 2 [Feb 1974)pp 355-361 A study was made of the oxidation kinetics of SmCo5 between 100 and 1125°C. During oxidation a composite subscale grows that consists of Sm203 fibres in a matrix of cobalt with fibres generally perpendicula to the subscaleintermetallic interface. The fibre size increased with oxidation temperature above 750°C. The growth of the scale follows a parabolic oxidation law. The high rates of growth suggest that it occurs by oxygen diffusion down the cobalt/oxide interfaces.
The present position of the development of aluminium reinforced with carbon fibres The tensile failure modes of metallgnatowitz, E. Aluminium, 11o150, matrix composite materials No 5 (May 1974) p 334 [supplement in Wright, M. A. and Wills, J. L. Journal English, p 17) of the Mechanics and Physics of Solids, Carbon fibre-reinforced aluminium Vo122, No 3 (May 1974) pp 161-176 should be suitable for use up to 500°C The strengths of individual boron fibres making it, for instance, an attractive extracted from various as-received and material for parts of the skin of superthermally-fatigued aluminium alloy conic aircraft which reach 550°C at matrix materials were measured. The Mach 4. After initially disappointing results are described in terms of a tests the theoretically calculated strengths Weibull distribution and strengths of are now being attained by pre-casting the composites made from these fibres are fibres or by chemical surface treatment. calculated in terms of lower and upper Problems associated with shaping, joint- bounds. Tests conducted on composite ing, corrosion etc still have to be solved, specimens indicate that strengths but broadly based use of such materials approaching the upper bounds can be still depends very much on the cost of the achieved in composites fabricated by raw materials and manufacturing processes, normal diffusion bonding techniques. Cyclic temperature changes effectively Strengths and failure mechanisms of a reduced the strength values towards the Co-15Cr-I 3 TaC directionally solidified lower bounds, and it is concluded that eutectic alloy this effect resulted fro~ the degradation Buchanan, E. R. and Tarshis, L. A. of the strength of the fibre/matrix bond. Metallurgical Transactions, Vol 5, No 6 [Jun 1974)pp 1413-1422 Transient stress states in composite A study was made of the tensile and creep stress/rupture properties of a Co-Cr-TaC Garmong, G. Metallurgical Transactions, aligned eutectic consisting of fibres of Vol 5, No 5 (May 1974) pp 1257-1258 TaC in a Co-Cr solid solution matrix. If the isothermal creep equations for Comparison with the tensile properties the individual components of a composof the pure matrix indicated that the iter are of a different form, then the fibres bear 80-90% of a tensile load on distribution of stress between the comthe composite. The tensile breaking ponents can be expected to change with strength of the fibres was calculated at time during the creep of the composite. 5700 MN/m 2 at room temperature, fall- This effect is analyzed theoretically and ing to 2000 MN/m 2 at 1235°C. The predictions of the stress redistribution stress-rupture properties of the composite made for metal matrix composites. at low stresses (-~ 140 MN/m 2) were superior to those of superalloys but were RESIN MA TRICES inferior at higher stress levels (-~ 350 MN/m2). This was found to be due to Bending of multi-layered belts a change in the rupture mechanism of Tabaddor, F. Fibre Science and the composite. At low stresses and high Technology, Vol 7, No 2 [Apr 1974) temperature the failure is thought to p 89 depend on matrix failure whereas at high The bending of multi-layered belts of stresses and lower temperatures fracture thin, stiff plies bonded with soft rubber is considered to originate in the fibres. plies is analysed mathematically and the analysis technique is applied to obtain Superconductivity composite of copper the bending stresses in a sandwich belt and niobium - a metallurgical approach as it bends round a pulley. The results Tsuei, C. C. J App Physics, Vo145, are compared with those obtained from No 3 [March 1974)p 1385 beam theory and the strain values preSuperconducting composites of niobium dicted are shown to be lower. It is noted
Novel morphology of Pb/Sn/Cd/Zn quaternary euteetic Fisher, D. J. and Kurz, W. Metallurgical Transactions, Vol 5, No 6 [June 19 74) pp 1508-1510 The quaternary eutectic, Pb, Sn, Cd, Zn, (28.6, 52.45, 16.7 and 2.25 weight % respectively) was grown directionally at between 0.05 and 2cm/h with a temperature gradient of 23°C/cm. The resulting microstructure consisted of aligned lamellae of Cd sandwiched between lamellae of Pb in a tin-rich matrix. Lamellae of Zn had grown at right angles to the Cd and Pb lamellae, so producing a 'lattice-work' appearance. Preparation and casting of metalparticulate non metal composites Mehrabian, R., Rick, R. G. and Flemings, M. C. Metallurgical Transactions, Vo15, No 6 [June 1974) pp 1899-1905 A method was developed for the preparation of composites of non-metallic particles dispersed in an alloy matrix. The composites were produced in a partly liquid state and so were suitable for casting and die-casting. The process consisted of vigorously mixing the particles, (A1203, SiC or glass) into a partially-molten alloy (A1/5 weight % St/ 2weight% Fe). The particles, which are initially not wetted by the liquid alloy, would normally segregate but in this
140
COMPOSITES. MAY 1975
that the shear strains in these belts are not considered in the beam theory.
Charpy impact characteristics of fiberglass reinforced plastics with an instrumented machine Hojo, H. et al. Proc of l 7th Japan Congress on Materials Research (Kyoto 1974)p 167 The impact energy of glass-reinforced polyester at low and high temperatures has been studied using a Charpy impact tester. Various fibre configurations were used ranging from unidirectional to random mat. Strain gauges were mounted on each side of the hammer and observations were made using a synchroscope. It is suggested that the load/time curve is important as well as the total energy absorption in studying frp materials.
Effects of watery environment on fatigue strength of frp Masuda, Y. Proc of17th Japan Congress on Materials Research (Kyoto 1974)p 172 The static and fatigue strength of frp consisting of glass cloth and polyester resin has been measured in tension, compression and bending, after immersion in plain and sea water. Saturation with plain or sea water was observed to occur after 4 0 - 1 0 0 days depending on
laminate thickness. There was a decrease of flexural and compressive strength in proportion to the water absorption, the final level being about 70-80% of its initial value. Little change in tensile strength due to water absorption was observed. The fatigue strength at 106 cycles was reduced to about 60% when saturated with water. No difference between plain and sea water was noticed.
On the study of indigenous natural fibre composites
Anon. Materials Engineering, Vol 78, No 6 (November 19 73) p 36 The materials, construction, applications and costs of honeycomb structures are reviewed with sections on facing materials, core materials and geometry, bonding and properties. Among the non-structural applications of honeycomb structures are as impact energy absorbers for rapidly decelerating objects, as radio frequency shields and as matrices for ablative materials and catalysts.
Paramasivam, T. and Abdul Kalam,
P. J. Fibre Science and Technology, Vol 7, No 2 (Apr 19 74) p 85 The application of natural fibres such as sisal, coconut and jute as reinforcements for low cost epoxy resin based composites has been studied. It is concluded that, since the densities of these fibres are about half of those of glass, the specific properties of these composites are sufficiently high to warrant further evaluation.
STRUCTURES
Honeycomb structures maintain strength while cutting weight
New type of continuous composite steel and concrete bridge Fried, A. Acier-Stahl-Steel, Vo139, No 11 (Nov 1974J p 482-481 A new type of continuous composite steel and concrete bridge has been developed in the Bridge Section of the Department of Main Roads, New South Wales, Australia. In this type of bridge simple supported steel beams are connected without field riveting, bolting or welding in such a way that full continuity and composite action of concrete deck slab and steel beams is achieved. Ease of erection and weight saving in steel beams and consequently greater economy and the feasibility of longer spans are made possible in composite steel and concrete bridges.
Abstracts of patents UK PA TEN TS
Method for forming refractory fibres (Arthur D. Little lnc) UK Pat 1 362 429 (7Aug 1974J Fibres suitable for metal reinforcement are made from materials (which cannot conveniently be melted in a crucible) by continuously feeding a rod into a heating zone, where the material melts and a fibre can be drawn from it. The radius of the rod does not exceed 6.7 times that of the fibre and the length of the molten zone is less than 5.7 times the fibre radius.
Reinforced plastic materials
Laminated materials
(Morganite Modmor Limited) UK Pat
(Lion Fat and Oil Company Limited)
1 362 531 (7Aug 1974) A rod is made by wrapping layers of resin impregnated glass cloth round a mandrel with carbon fibres disposed between the layers. The nature, length, or concentration of the fibres may vary from one part of the rod to another to give different physical properties.
UK Pat 1 362 835 (7Aug 1974) A constructional laminate is made from layers of thermoplastic resin sheets containing calcium sulphite and/or gypsum. The sheets are anisotropic as a result of being orientated in a single direction before laminating.
High inorganic filler content
Filled film product and process
Electrodeposited composite coatings of metal and graphite fluoride (C. Uyemura and Co Ltd) UKPat 1 362 558 (7Aug 1974)
(E. I. Dupont de Nemours and Company) UK Pat I 362 457 (7Aug 1974} A packaging film is made by blending an a-mono-olefine polymer with 26 to 50% by weight of a particulate f'fller. preferably a clay, forming a film which is biaxially stretched until it has a void content of at least 30%.
A self-lubricating surface is produced by making a dispersion of graphite fluoride powder, with a particle size less than 10 ~tm in a metal plating bath containing a water soluble surfactant having a fluorine/carbon bond in the molecule and electrodepositing the metal and powder simultaneously.
High impact and tensile strength materials are made by mixing an ethylene/ propylene copolymer, particularly if a block copolymer, having an ethylene content of 0.1 to 30% with at least 30% of an inorganic filler, excluding mica, having a particle size of 20 #m or less.
COMPOSITES. M A Y 1975
composition (Mitsubishi Petrochemical Co. Ltd)
UK Pat 1 362 912 (7Aug 1974J
141