Composites of super purity aluminiumunidirectionally reinforced with Altex or Nextel 610 continuousalumina based fibre have been made by liquid metal infiltration.The composites were well consolidated, with fibre volumefractions V_f of 0 centre dot 4 and 0 centre dot 6 for the Altexcomposites and 0.7 for the Nextel composite, the higher valuesbeing obtained where performing involved the use of sized fibretows. Matrix porosity was very low and there was no evidenceof any deleterious reaction product having formed at thefibre/matrix interface. Monotonic longitudinal tensile tests of thecomposites gave Young's modulus values between 125 and 250GPa, in line with rule of mixtures (ROM) predictions andevidence of effective load transfer between fibres. The onset ofyielding in longitudinal composites was commensurate with theyield stress of unreinforced super purity aluminium for V_f= 0centre dot 4 (approx 20 MPa), but increased to 225 MPa forV_f= 0 centre dot 7. The tensile strengths of the Altexcomposites were 760 and 930 MPa, values in accord with ROMpredictions based upon equal load sharing of fibres up to themean filament failure stress. Although the Nextel composite hada higher tensile strength of 1250 MPa, this was significantlylower than the ROM value of1650 MPa and was betterdescribed by fibre 'bundle' theory. Predictions of theaccumulation of fibre damage, by statistical analysis, indicatedthat filament breakage commenced at an applied stress ofapprox 50 MPa for the Altex composite and approx 500 MPa forthe Nextel composite. Despite damage at the lower stress,however the Altex composites were able to tolerate many more'double' fibre breaks than the Nextel composite, the failure ofwhich coincided with the onset of the first double break.Transverse tensile tests of the composites gave Young's modulusvalues between 80 and 170 GPa, in line with ROM predictions.The yield stress increased with increasing V_f from 10 to 60MPa, this behaviour being attributed to plane strain deformationcaused by the virtually non-deformable fibres constrainingmatrix flow. The tensile strengths showed a similar trend, with84 MPa for V_f= 0 centre dot 4 increasing to 168 MPa for V_f= 0 centre dot 7.
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