A new process for manufacturing continuously reinforced Aluminium alloy MMC

Abstract EN

A fabrication method for High Strength (H.S.) carbon fibre-aluminium composites was investigated.

An unmodified high strength carbon fibre with 7-20 microtis in diameter was used, and the combination of fibre coating with sufficient Al-matrix material and hot-consolidation was adopted in the present study.

The method was improved so as to accurately control the coating thicknesses and volume fraction of fibres in the fabricated composites.

Composites with Fibre volume fractions between 20 and 70% were achieved by means of this method.

The influence of the consolidation parameters (pressure, temperature, and time) was evaluated.

The conditions in which the micro structural consolidation quality was best, were found to be at temperature of 540° C , 3 MPa pressure and time of 60 minutes for C-A1(1050) composite and 540° C, 6 MPa and 6 minutes for C-A1(35<3) composites.

Microstruoture examination of fabricated composites showed no evidence present of fibre degradation, damage, pores, and chemical reaction between fibre-matrix interfaces.

The results obtained for the carried out mechanical tests indicate a significant increase in the values of tensile, fracture toughness, and impact energy in the parallel and perpendicular to fibre direction, respectively, of such composites, and showed that the quality of these composites was comparable, if not, superior to that of composites made by liquid infiltration, slurry impregnation and hot pressing, or squeeze casting techniques.

Fracture surface SEM examinations of both tested composites revealed the presence of pulled out fibres, debonded fibres and multiple fibre fracture which indicate the presence of mechanical bonding at fibre-matrix interfaces.

This and matrix ductility proved to be an energy absorbing mechanism resulting in high values of mechanical properties of such composites.