Abstract
The strength and hardness of the composites were investigated. The present results showed that the strength and hardness of the composites increased with the addition of graphene nanosheets. Graphene nanosheets may act as obstacles for the dislocation movement and finally promote for the dislocations accumulation having an important role for the improvement of mechanical properties of the composites. The difference in thermal expansion coefficient was also responsible for the improvement of the strength and hardness of the composites.