Improve microstructure and mechanical properties of al-a332–alloy reinforced AL2o3 micro and Nano composites fabricated by stir casting

Abstract EN

Aluminium matrix composites (AMCs) reinforced with micro and nano-sized Al2O3 particles are widely used for high performance applications such as automotive, military, and aerospace and electricity industries because of their improved physical and mechanical properties.

The major problem in fabricating metal matrix composites by liquid phase is the poor readability which leads to the nonuniform distribution of the particles.

In order to improve the microstructure and mechanical properties of composite, firstly improve the wettability and distribution of reinforcement particles within the matrix.

Three steps were applied in stir casting process to avoid agglomeration and segregation of particles.

The process included heat treatment of micro and nano Al2O3 particles, injection of heat-treated particles within the molten A332 aluminium alloy by inert argon gas and stirring the melt at suitable speed.

In the present work, nano and micro-composites (A332/Al2O3) with different weight percent of particles were fabricated by stir-casting techniques.

Micro structural characterization was investigated by optical (OP) and scanning electron microscopy (SEM).

Tensile, hardness tests were carried out in order to identify mechanical properties of the composites.

The results of micro structural study revealed uniform distribution, grain refinement and low porosity in micro and nano-composite specimens.

The mechanical results showed that the addition of alumina (micro and nano) led to the improvement in yield strength, ultimate tensile strength, and hardness.

It was indicated that type of fabrication process and particle size were the effective factors influencing on the mechanical properties.

Decreasing alumina particle size and using steps of stir casting method- process obtained the best mechanical properties.