Aluminum metal matrix composites (AMCs) are regarded as candidate materials for aerospace and automotive
applications owning to their superior properties, such as high specific modulus specifically at high temperatures, good
strength and low wear rates. AMCs have been prepared by liquid metal route such as pressureless infiltration, squeeze
casting, stir casting, spray forming, etc. Each of these processes has their own advantages and limitations. The choice of
the fabrication techniques is dictated by production cost, process efficiency, the quality desired in the product and their
applications. AMCs cast from the liquid state are of interest because of their relatively low processing cost and ease in
manufacturing. In the present project, Aluminum A356 and zirconia nano particles were selected as raw materials.
Zirconia nano particles were founded to be a promising candidate due to its high hardness, high modulus of elasticity and
excellent thermal stability. Samples of composites was made at different amount of zirconia's particles (0, 1.5, 2.5, 5vol
%) and temperature of casting were 800, 850 and 950°C. Microstructure of composite specimens was examined using
SEM and optical microscopy. Chemical composition was investigated by XRD method. Physical properties such as
density and porosity were determined by Archimedes and image analyzing methods. Mechanical properties such as
tensile strength, hardness and toughness were determined. The experimental results show that the mechanical properties
like tensile strength and hardness markedly improved by adding zirconia nano particles. The maximum was for samples
with 5vol% of nano particles were casted at 850°C. Fracture toughness decreased by addition of zirconia nano particles.