Konstantin Borodianskiy

Abstract:

Carbide nanoparticles were added to the hypoeutectic Al-Si melts in the amount of 0.001-0.1 wt.%. A fine microstructure of the alloy was achieved by a modification process as a result of direct influence of the nanoparticles to the metal crystallization process. Macro- and micro- structures of the aluminium alloy specimens fabricated by casting process were investigated and their mechanical properties were tested. After T6 heat treatment of the obtained modified alloys, the following properties have been achieved: the elongation increased by 20-60% in different parts of a cast whiles the tensile strength remained unchanged.
A high resolution electron microscopy (HR-TEM) study indicated a high concentration of dislocations near grain boundaries in the modified alloy samples. These grain boundaries seem to serve as obstacles to dislocation motion. It was therefore concluded that the mechanical properties improvement of the aluminum alloy modified with carbide nanoparticles can be explained by the grain-size strengthening mechanism.