Application of compocasting and cross accumulative roll bonding processes for manufacturing high-strength, highly uniform and ultra-fine structured Al/SiC_p nanocomposite

摘要

In order to achieve a refine microstructure along with improvement of mechanical properties of cast Al/ 2 vol％ SiC_p nanocomposite, cross accumulative roll bonding (CARB) process was employed. Optical and electron microscopies, the Archimedes method, and tensile test were used to evaluate microstructural evolution and mechanical properties of the nanocomposites during CARB cycles. Results showed that the microstructure of the nanocomposite after eight cycles of CARB had homogenous distribution of SiC nanoparticles in aluminum matrix without any remarkable porosity. The results of transmission electron microscopy showed that ultra-fine structured Al/SiC_p nanocomposite was successfully achieved by employing eight cycles of CARB technique. Also, the tensile strength and the elongation of the nanocomposite increased as the number of CARB cycles increased. After eight CARB cycles, ultimate tensile strength and the elongation values reached 354 MPa and 6.9％, which were 3.22 and 3.28 times greater than those of the as-cast nanocomposites, respectively. Strengthening mechanisms were explained by strain hardening, grain refinement, reinforcing role of nanoparticles, uniformity of reinforcement and porosity.