- Email: [email protected]
Creep and stress rupture of a mechanically alloyed oxide dispersion and precipitation strengthened nickel-base superalloy
fibre orientation, with respect to loading direction, are also presented. It is shown that there is 40-65% decrease in moduli and also presented. It is shown that there is a 40-65% decrease in moduli and strength at Tg in all cases except for the unidirection laminates in the fibre direction where the reduction in the modulus Ell is only 10% at
rg. Use of mica in poly (vinyl chloride) Bataille, P. and Bui, T.V. Polymer Composites Vol 2 No 1 (January 1981) pp 8-12 The effect of gradual replacement of calcium carbonate filler with mica in highly-filled PVC was studied. It was shown that the mica improved the fluxing time of the formulation by a factor of three without significantly affecting the equilibrium or maximum torque. Optimum results were obtained with a mixture of mica/calcium carbonate. Vibration of eccentrically stiffened laminates Chao, C.C. and Lee J.C. Journal o f Composite Materials Vol 14 (1980) pp 233-244 This paper presents a dynamic analysis of eccentrically stiffened laminates. The natural frequencies and mode shapes are derived. The vibration response is shown to be reducible (by changing natural frequencies) by incorporating stiffeners without appreciable weight penalty. Vibrations of fibre-reinforced plates of complicated shape Laura, P.A.A., Luisoni, L.E. and Sarmiento, Sanchez, G. Fibre Science and Technology Vol 14 No 3 (April 1981) pp 165-170 Orthotropic has been used to determine the fundamental frequency of transverse vibration of thin, elastic plates with fibre-reinforcement in two o r t h o g o n a l directions. Numerical results are presented for clamped and simply supported plates of regular polygonal shape. It is shown that the polynomial co-ordinate functions used yield results of greater accuracy than those obtained by the present authors using simply supported edges. Water sorption characteristics of GRIP composite: effect of outdoor weathering Blaga, A. Polymer Composites Vol 2 No 1 (January 1981)pp 13-17 Following outdoor weathering for 3 years, it was found that weathered glass fibre-reinforced polyester absorbed larger amounts of water vapour than
COMPOSITES. JULY 1981
non-weathered sheets, and at higher rates. This leads to accelerated stressfatigue in the composites.
METAL/VIA TRICES Analysis of centre-notched monolayers with application to boron/aluminium composites Reedy, E.D. Jr. Journal of the Mechanical Physics of Solids Vol 28 (1980) pp 265-286 A method for calculating the stresses in a notched monolayer of unidirectional, filamentary composite is described. Calculations for a boron/aluminium monolayer identify widespread matrix yielding and a notch-fibre stress concentration whose magnitude depends on the nature of the work-hardening matrix. The model which applied to centre-notched, multilayered, unidirectional boron/aluminium, predicts a non-linear response of the notch opening displacement to load. The model also provides reasonable estimates of notched composite failure strengths.
Creep and stress rupture of a mechanically alloyed oxide dispersion and precipitation strengthened nickel-base superalloy Howson, T.E., Mervyn, D.A. and Tien, J.K. Metallurgical Transactions Vol 11A No 9 (September 1980) pp 16091616 The creep and stress rupture behaviour of a mechanically alloyed oxide dispersion strengthened and precipitation s t r e n g t h e n e d n i c k e l - b a s e alloy, MA6000E, was studied at temperatures of 760 and 1093°C. At 760°C the analysis indicated that the creep strength was controlled by the high volume fraction of precipitates and the contribution to the creep strength from the oxide dispersion was small, whilst the 1093 C the creep strength was derived mainly from the inert oxide dispersions.
Growth crystallography of a directionally solidified Fe-Nb-Ni eutectic alloy Tewari, Surendra N. Metallography Vol 13 No 4 (December 1980) pp 379-381 The author reports the growth crystallography observed in a directionally solidified eutectic alloy. The microstructure of the directionally solidified Fe-16.5 Nb-15.4 Ni alloy has been investigated with the aid of scanning
and transmission electron microscopy. The orientation relationship between the two phases and the alloy growth direction were obtained from electron diffraction patterns.
A method for measuring the planar interparticle distance between plate-like precipitates Torronen, K. Metallography Vol 13 No 4 (December 1980) pp 329-344 A method for measuring and calculating the planar interparticle distance between plate-like precipitates has been developed. The method utilizes transmission electron microscopy of thin foils; no information of the volume fraction of the particles is needed. The applicability of this method in the case of squared plate-like vanadium carbides in a Cr-Mo-V alloyed steel was assessed. Changes in yield strengths, seen after different temperings, are attributed to changes in the planar interparticle spacings and in the sizes of the vanadium carbide plates. Suppression of fatigue crack growth in all metal composites using pre-stressed reinforcing members Morley, J.G. and McColl, I.R. Engineering Fracture Mechanics, Vo114 (1981) pp 1-25 Pre-stressed reinforcing members are shown to supress the growth of existing fatigue cracks in laboratory specimens by several orders of magnitude. The engineering potential of this type of composite is critically discussed with reference to fibrous composites.
NATURAL COMPOSITES Electron microscopy of fibril/matrix interactions in a natural composite, insect cuticle Hillerton, J.E. Journal of Materials Science Vol 15 No 12 (December 1980) pp 3109-3112 The extent and stability of the interactions between the fibrils and the matrix of insect cuticle are shown. The fibrous phase is shown to consist of a polysaccharide with a very closely attached protein coat. The matrix protein then, because of the affinity of protein for protein, bonds well to the fibrils to produce an efficient composite. The toughness of tooth enamel, a natural fibrous composite Fox, P.G. Journal o f Materials Science Vol 15 No 12 (December 1980) pp 3113-3121 It is suggested that the mechanical
211
rg. Use of mica in poly (vinyl chloride) Bataille, P. and Bui, T.V. Polymer Composites Vol 2 No 1 (January 1981) pp 8-12 The effect of gradual replacement of calcium carbonate filler with mica in highly-filled PVC was studied. It was shown that the mica improved the fluxing time of the formulation by a factor of three without significantly affecting the equilibrium or maximum torque. Optimum results were obtained with a mixture of mica/calcium carbonate. Vibration of eccentrically stiffened laminates Chao, C.C. and Lee J.C. Journal o f Composite Materials Vol 14 (1980) pp 233-244 This paper presents a dynamic analysis of eccentrically stiffened laminates. The natural frequencies and mode shapes are derived. The vibration response is shown to be reducible (by changing natural frequencies) by incorporating stiffeners without appreciable weight penalty. Vibrations of fibre-reinforced plates of complicated shape Laura, P.A.A., Luisoni, L.E. and Sarmiento, Sanchez, G. Fibre Science and Technology Vol 14 No 3 (April 1981) pp 165-170 Orthotropic has been used to determine the fundamental frequency of transverse vibration of thin, elastic plates with fibre-reinforcement in two o r t h o g o n a l directions. Numerical results are presented for clamped and simply supported plates of regular polygonal shape. It is shown that the polynomial co-ordinate functions used yield results of greater accuracy than those obtained by the present authors using simply supported edges. Water sorption characteristics of GRIP composite: effect of outdoor weathering Blaga, A. Polymer Composites Vol 2 No 1 (January 1981)pp 13-17 Following outdoor weathering for 3 years, it was found that weathered glass fibre-reinforced polyester absorbed larger amounts of water vapour than
COMPOSITES. JULY 1981
non-weathered sheets, and at higher rates. This leads to accelerated stressfatigue in the composites.
METAL/VIA TRICES Analysis of centre-notched monolayers with application to boron/aluminium composites Reedy, E.D. Jr. Journal of the Mechanical Physics of Solids Vol 28 (1980) pp 265-286 A method for calculating the stresses in a notched monolayer of unidirectional, filamentary composite is described. Calculations for a boron/aluminium monolayer identify widespread matrix yielding and a notch-fibre stress concentration whose magnitude depends on the nature of the work-hardening matrix. The model which applied to centre-notched, multilayered, unidirectional boron/aluminium, predicts a non-linear response of the notch opening displacement to load. The model also provides reasonable estimates of notched composite failure strengths.
Creep and stress rupture of a mechanically alloyed oxide dispersion and precipitation strengthened nickel-base superalloy Howson, T.E., Mervyn, D.A. and Tien, J.K. Metallurgical Transactions Vol 11A No 9 (September 1980) pp 16091616 The creep and stress rupture behaviour of a mechanically alloyed oxide dispersion strengthened and precipitation s t r e n g t h e n e d n i c k e l - b a s e alloy, MA6000E, was studied at temperatures of 760 and 1093°C. At 760°C the analysis indicated that the creep strength was controlled by the high volume fraction of precipitates and the contribution to the creep strength from the oxide dispersion was small, whilst the 1093 C the creep strength was derived mainly from the inert oxide dispersions.
Growth crystallography of a directionally solidified Fe-Nb-Ni eutectic alloy Tewari, Surendra N. Metallography Vol 13 No 4 (December 1980) pp 379-381 The author reports the growth crystallography observed in a directionally solidified eutectic alloy. The microstructure of the directionally solidified Fe-16.5 Nb-15.4 Ni alloy has been investigated with the aid of scanning
and transmission electron microscopy. The orientation relationship between the two phases and the alloy growth direction were obtained from electron diffraction patterns.
A method for measuring the planar interparticle distance between plate-like precipitates Torronen, K. Metallography Vol 13 No 4 (December 1980) pp 329-344 A method for measuring and calculating the planar interparticle distance between plate-like precipitates has been developed. The method utilizes transmission electron microscopy of thin foils; no information of the volume fraction of the particles is needed. The applicability of this method in the case of squared plate-like vanadium carbides in a Cr-Mo-V alloyed steel was assessed. Changes in yield strengths, seen after different temperings, are attributed to changes in the planar interparticle spacings and in the sizes of the vanadium carbide plates. Suppression of fatigue crack growth in all metal composites using pre-stressed reinforcing members Morley, J.G. and McColl, I.R. Engineering Fracture Mechanics, Vo114 (1981) pp 1-25 Pre-stressed reinforcing members are shown to supress the growth of existing fatigue cracks in laboratory specimens by several orders of magnitude. The engineering potential of this type of composite is critically discussed with reference to fibrous composites.
NATURAL COMPOSITES Electron microscopy of fibril/matrix interactions in a natural composite, insect cuticle Hillerton, J.E. Journal of Materials Science Vol 15 No 12 (December 1980) pp 3109-3112 The extent and stability of the interactions between the fibrils and the matrix of insect cuticle are shown. The fibrous phase is shown to consist of a polysaccharide with a very closely attached protein coat. The matrix protein then, because of the affinity of protein for protein, bonds well to the fibrils to produce an efficient composite. The toughness of tooth enamel, a natural fibrous composite Fox, P.G. Journal o f Materials Science Vol 15 No 12 (December 1980) pp 3113-3121 It is suggested that the mechanical
211