the structural and mechanical properties of al-2.5%wt. b4c met-al matrix nano-composite fabricated by the mechanical alloying

In this study, aluminum (al) matrix reinforced with microparticles (30 µm) and nanoparticles (50 nm) boron carbide (b4c) were used to prepare al2.5%wt., b4c nanocomposite and microcomposite, respectively, using mechanical alloying method. the mixed powders were mechanically milled at 5, 10, 15 and 20 hrs. the xrd results indicated that the crystallite sizes of both the microcomposite and nanocomposite matrix decreased with increasing milling time, showing 55 nm and 40 nm, respectively. mechanical testing results showed an increase in the flexural strength from 98 to 164 and 115 to 180 mpa, and an increase in the hardness from 60 to 118 and 75 to 130 hv for microcomposite and nanocomposite, respectively. the results indicate that the strength and hardness of the nanocomposite are higher than those of the microcomposite due to the presence of the fine particles.