  The influence of a modifier based on WC nanoparticles was investigated using
bulk Al in a real industrial process using a commercial AlSi hypoeutectic
alloy. The modifier was prepared by hot extrusion approach. Its influence was
investigated on Al and on commercial Al A356 alloy. The mechanical properties
of the Al A356 alloy modified with WC nanoparticles was determined after T6
heat treatment and compared with an unmodified specimen of the same alloy. The
results obtained in the modified Al A356 alloy reveal unusual behavior of the
mechanical properties, where the elongation of the alloys improved by 32% 64%,
while the tensile and the yield strengths remained unchanged. This behavior was
attributed to a grain size strengthening mechanism, where strengthening occurs
due to the high concentration of grain boundaries, which prevent the
dislocations motions in the metal lattice.
