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The hardness of Al-Si eutectic alloys
Rolling AI-A1, Fe directionally solidified eutectic causes the fibres to fracture into progressively shorter lengths and the formation of dense dislocation tangles between the fibres. These concentrated tangles ultimately form dislocation domains which polyganise into low angle sub-grain boundaries,
Deformation parameters in single steel wire/copper matrix composites Ochiai, S. and Murakami, Y. Journal of Materials Science, Vol 14 (1979) pp 1187-1191 By using single carbon-steel fibre/ copper matrix composites, the parameters controlling dislocation motions in the fibre, matrix, and composite, namely flow, internal and effective stresses, changes in flow stress due to change in strainrate or temperature, stress exponent of strain-rate, effective stress component of dislocation velocity, activation volume, and enthalpy were measured at the stage in which the mechanical interaction between the components was negligible. It was found that all the composite properties were determined only by the properties of the components and for each parameter, a modified rule of mixtures was derived. D i r e c t i o n a l s o l i d i f i c a t i o n of aluminium-nickel eutectie alloys using electroslag remelting Rohatgi, P.K., Bhutani, A.K. and Abraham, K.P. Metallurgical Transactions, Vol IOA (March 1979) pp 333-342 Directionally solidified, specifically grain aligned AI-6 wt. % Ni eutectic alloy specimens have been fabricated in a laboratory scale ESR unit. The important production parameters have been identified and the mechanical properties of the material reported, Fabrication and eharacterisation of in situ s u p e r c o n d u c t i n g multifilamentary copper-niobium wires Roberge, R. and Fihey, J.L. Journal of Applied Physics, Vol 50 No 1 (January 1979) pp 406-409 In situ superconducting, multifilamentary Cu-17 wt% Nb wires have been produced by induction melting a mixture of the powders and then swaging the resultant rod. The dramatic increase in critical current density atliquid helium temperature
COMPOSITES. OCTOBER 1979
is accounted for by a model based on the nonhomogeneous deformation of the niobium network. The evolution of the I-V curves from a broad transition to a sharp transition with increasing deformation is explained in terms of the geometry of the niobium chains,
boron fibres has been investigated. The results are described in terms of the critical stress intensity, K o. Values of K o that depended on the dimensions of the specimen were obtained. It was concluded that, for the size of the specimen tested, the values of the critical stress intensity did not reflect any basic material
Failure of centre notched specimens of 6061 aluminium reinforced with unidirectional boron fibres Wright, M.A. and Welch D. Fibre Science and Technology V o l l l No 6 (November 1978) pp 447-461 The fracture of 6061 aluminium alloy reinforced with unidirectional boron fibres was investigated using a technique based on a critical stress intensity, Kc. Criticalstress intensity factors were obtained by substituting the failure stress and the initial crack length into the appropriate expression for Kc. Values were obtained that appeared to depend on the dimensions of the specimens, A model of specimen deformation was developed based on a shear lag analysis which enabled both the extension of the specimens and the fracture stresses to be predicted. (Authors' abstract)
property.
Fracture of a unidirectional B-AI composite with a circular hole Broockman, E.C. and Sierakowski, R.L. Fibre Science and Technlogy, Vo112 No 1 (January 1979) ppl-10 Data are presented from a testing programme investigating fracture of unidirectionalB-Alcompositeswith central circular cutouts. The B-AI strips studied were found to exhibit stress concentration size effects previously reported for epoxy matrix composites. Comparisons of the data with a point and average stress fracture criteria are examined. An expression for the approximate stresses in an orthotropic plate has been substituted in a recently advanced fracture criterion and found to be in good agreement with experimental data. (Authors' abstract)
The fracture of boron fibrereinforced 6061 aluminium alloy Wright, M.A., Welch, D. and Jollay, J. Journal of Materials Science, Vol 14 (1979) pp 1218-1228 The fracture of 6061 aluminium alloy reinforced with unidirectional and cross-plied 0/90 °, 0/90/+45 °
The hardness of AI-Si eutectic alloys Vnuk, F., Sahoo, M., Merwe, Van de R. and Smith, R.W. Journal of M a t e r u a lScience, s Vo114 (1979) pp 975-982 The Vickers hardness values of A1-Si eutectic alloys, solidified unidirectionally at various rates were determined. It is shown that there is no close correlation of hardness and strength over the range of growth rates used, although similar trends are seen between hardness and compressive yield strength. It isconcluded that caution should be exercised when inferring strength from hardness data. The microstructure and mechanical properties of Nb~Sn filamentary superconducting composites West, A.W. and Rawlings, R.D. Journal of Materials Science, Vol 14 (1979) pp 1179-1186 The deformation processes in filamentary superconducting composites at both room temperature and 4.2K were studied using TEM and SEM. The Nb3Sn failed in an intergranular manner without any prior dislocation activity and radial cracks formed in the NB3Sn layer during deformation were stopped by the unreacted niobium central core. Variations in ductility between different composites were explained in terms of the volume fractions of unreacted niobium. Monotectic composite growth Cahn, J.W. Metallurgical Transactions, Vol IOA (January 1979) pp 119-121 The theoretical factors in monotectic composite growth are reexamined and techniques of overcoming the problem of perfect wetting of the solid by the monotectic liquid are discussed. The use of high velocities, applied pressure and ternary additions are proposed to facilitate monotectic composite fabrication.
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Deformation parameters in single steel wire/copper matrix composites Ochiai, S. and Murakami, Y. Journal of Materials Science, Vol 14 (1979) pp 1187-1191 By using single carbon-steel fibre/ copper matrix composites, the parameters controlling dislocation motions in the fibre, matrix, and composite, namely flow, internal and effective stresses, changes in flow stress due to change in strainrate or temperature, stress exponent of strain-rate, effective stress component of dislocation velocity, activation volume, and enthalpy were measured at the stage in which the mechanical interaction between the components was negligible. It was found that all the composite properties were determined only by the properties of the components and for each parameter, a modified rule of mixtures was derived. D i r e c t i o n a l s o l i d i f i c a t i o n of aluminium-nickel eutectie alloys using electroslag remelting Rohatgi, P.K., Bhutani, A.K. and Abraham, K.P. Metallurgical Transactions, Vol IOA (March 1979) pp 333-342 Directionally solidified, specifically grain aligned AI-6 wt. % Ni eutectic alloy specimens have been fabricated in a laboratory scale ESR unit. The important production parameters have been identified and the mechanical properties of the material reported, Fabrication and eharacterisation of in situ s u p e r c o n d u c t i n g multifilamentary copper-niobium wires Roberge, R. and Fihey, J.L. Journal of Applied Physics, Vol 50 No 1 (January 1979) pp 406-409 In situ superconducting, multifilamentary Cu-17 wt% Nb wires have been produced by induction melting a mixture of the powders and then swaging the resultant rod. The dramatic increase in critical current density atliquid helium temperature
COMPOSITES. OCTOBER 1979
is accounted for by a model based on the nonhomogeneous deformation of the niobium network. The evolution of the I-V curves from a broad transition to a sharp transition with increasing deformation is explained in terms of the geometry of the niobium chains,
boron fibres has been investigated. The results are described in terms of the critical stress intensity, K o. Values of K o that depended on the dimensions of the specimen were obtained. It was concluded that, for the size of the specimen tested, the values of the critical stress intensity did not reflect any basic material
Failure of centre notched specimens of 6061 aluminium reinforced with unidirectional boron fibres Wright, M.A. and Welch D. Fibre Science and Technology V o l l l No 6 (November 1978) pp 447-461 The fracture of 6061 aluminium alloy reinforced with unidirectional boron fibres was investigated using a technique based on a critical stress intensity, Kc. Criticalstress intensity factors were obtained by substituting the failure stress and the initial crack length into the appropriate expression for Kc. Values were obtained that appeared to depend on the dimensions of the specimens, A model of specimen deformation was developed based on a shear lag analysis which enabled both the extension of the specimens and the fracture stresses to be predicted. (Authors' abstract)
property.
Fracture of a unidirectional B-AI composite with a circular hole Broockman, E.C. and Sierakowski, R.L. Fibre Science and Technlogy, Vo112 No 1 (January 1979) ppl-10 Data are presented from a testing programme investigating fracture of unidirectionalB-Alcompositeswith central circular cutouts. The B-AI strips studied were found to exhibit stress concentration size effects previously reported for epoxy matrix composites. Comparisons of the data with a point and average stress fracture criteria are examined. An expression for the approximate stresses in an orthotropic plate has been substituted in a recently advanced fracture criterion and found to be in good agreement with experimental data. (Authors' abstract)
The fracture of boron fibrereinforced 6061 aluminium alloy Wright, M.A., Welch, D. and Jollay, J. Journal of Materials Science, Vol 14 (1979) pp 1218-1228 The fracture of 6061 aluminium alloy reinforced with unidirectional and cross-plied 0/90 °, 0/90/+45 °
The hardness of AI-Si eutectic alloys Vnuk, F., Sahoo, M., Merwe, Van de R. and Smith, R.W. Journal of M a t e r u a lScience, s Vo114 (1979) pp 975-982 The Vickers hardness values of A1-Si eutectic alloys, solidified unidirectionally at various rates were determined. It is shown that there is no close correlation of hardness and strength over the range of growth rates used, although similar trends are seen between hardness and compressive yield strength. It isconcluded that caution should be exercised when inferring strength from hardness data. The microstructure and mechanical properties of Nb~Sn filamentary superconducting composites West, A.W. and Rawlings, R.D. Journal of Materials Science, Vol 14 (1979) pp 1179-1186 The deformation processes in filamentary superconducting composites at both room temperature and 4.2K were studied using TEM and SEM. The Nb3Sn failed in an intergranular manner without any prior dislocation activity and radial cracks formed in the NB3Sn layer during deformation were stopped by the unreacted niobium central core. Variations in ductility between different composites were explained in terms of the volume fractions of unreacted niobium. Monotectic composite growth Cahn, J.W. Metallurgical Transactions, Vol IOA (January 1979) pp 119-121 The theoretical factors in monotectic composite growth are reexamined and techniques of overcoming the problem of perfect wetting of the solid by the monotectic liquid are discussed. The use of high velocities, applied pressure and ternary additions are proposed to facilitate monotectic composite fabrication.
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