Abstract
An experimental investigation was carried out to assess the self-healing characteristics of
aluminium hybrid composites reinforced primarily with mixed proportion of silica sand and
bamboo leaf ash. Charpy impact test samples with 45° notch were machined from the
aluminium hybrid composites and a ϕ1mm hole was drilled at 1mm away from the notch. Two
different self-healing treatments were given to the test samples prepared from the composites.
In the first treatment, a 3mm diameter hole was drilled along the sample and a low melting
point alloy (60Sn-40Pb) which served as secondary reinforcing material was pierced into the
hole and then heat treated at a temperature of 250°C. The second treatment that was adopted
involved subjecting the test samples to two-steps under-ageing treatment. The first step
involved ageing at 160°C for 15 minutes and quenched in water. Thereafter, the second ageing
treatment was carried out at 50°C for 24h. The samples were then subjected to Charpy impact
testing. The results show that the composites had lower absorbed energy compared with Al-
Mg-Si alloy. Self-healing treatment improved the energy absorbed in healed samples when
compared to the damaged samples. Although, the under-aged samples had a slightly higher
absorbed energy in comparison with the samples containing 60Sn-40Pb, the presence of silica
sand and bamboo leaf ash did not have significant influence on the absorbed energy. The
highest healing efficiency obtained using the low melting point alloy approach was 61%.