Plastic flow and work hardening of Al alloy matrices during ultrasonic consolidation fibre embedding process

SiC fibres and single mode (SM) optical fibres were successfully embedded in Al alloys matrices through ultrasonic consolidation (UC). The plastic flow of Al alloy matrices was visualized after anodization by optical microscopy with polarized light. Grain and sub-grain sizes of Al alloys before and after UC and work hardening of matrices due to plastic flow during UC process, were studied. The results show that UC process increases the hardness of alloy matrices, especially at regions proximal to fibres, with work hardening following the Hall-Petch relationship for both grains and sub-grains. During UC process, work hardening is mainly caused by bulk plastic deformation with no significant effect from friction at foil/foil interface. For the consolidated materials tested, work hardening in a 3003 O matrix is higher than that in a 6061 O matrix. In addition, plastic deformation of a 3003 O matrix in SM fibre embedded samples is smaller than that in SiC fibre embedded samples, which may have been influenced by the different embedding processes.