Study on Sintering Behavior of Alumina Particle Reinforced Aluminum Matrix Composites and Its Properties.

Aluminium matrix composites (AMC) are very attractive due to high strength to weight ratio and
have potential for automotive and aerospace industries. In this study, alumina particles reinforced
aluminium were developed using powder metallurgy technique. The alumina particles were
reinforced in the ranges of 2.5% to 10% of volume fraction. The materials were characterized
using particle size analyzer and scanning electron microscope for particle size, distribution,
shape and surface. A homogenous mixture of aluminium and alumina were prepared and
compacted at SOOMPa. The compacted parts were sintered at the temperature ranging from
550°C to 650°C under nitrogen atmosphere for two hours to study the behaviour of materials
density, shrinkage, microstructure and hardness. In order for hardness test, micrograph and
energy dispersive X-ray (EDX) to be conducted, surface preparation for the sintered parts is
required such as mounting, grinding and polishing. The study yielded that the optimum sintering
temperature is 580°C. The composites sintered at 580°C achieved the highest theoretical density
and hardness value. The composites also produced the least shrinkage with below 1%
controllable shrunk. The micrograph taken by SEM of the composites sintered at 580°C showed
smooth microstructure produced, large pore spaces or void is eliminated and also with greater
interparticle bonding. The results also showed that all density of the composites were increased
after sintering process and the composite produced shrinkage with no impurities presented
throughout the experiment.