Experimental and finite element analysis of mechanical and fracture behavior of SiC particulate filled A356 alloy composites: Part I

In the present study, silicon carbide (SiC) filled cast aluminum (A356) alloy composites were fabricated using stir casting technique by varying SiC weight percentages from 0wt.% to 25wt.% at a range of 5wt.%, respectively. The spherical shaped SiC particles of 60 mu m size were uniformly mixed with the semi-solid alloy by mechanical stirrer. The physical and mechanical properties along with the fracture toughness of SiC filled A356 alloy composite were evaluated experimentally and compared with finite element analysis results for the validation purpose. It was found that the void content of A356 alloy composites varied from 1.01% to 2.69% and hardness from 21.25 HRB to 33 HRB with the increased SiC wt.% from 0% to 25%. The maximum experimental value of Young's modulus and flexural strength at 25wt.% SiC filled A356 alloy composite was found to be 150.55MPa and 315.94MPa, respectively. Impact energy of the SiC filled A356 alloy composite also increased from 3.92J at 0wt.% to 7.82J at 25wt.% SiC. It was established that the stress intensity factor for unfilled and SiC filled A356 alloy composites increases with the increased crack length for 0-25wt.% SiC content. The tensile and flexural behavior of the composite is simulated by three-dimensional (3D) unit cell model using appropriate boundary condition in ANSYS. Finally, stress intensity factor for the crack propagation is determined using 2D simulation of single side edge cracked specimen in compact tension. The maximum percentage error for tensile strength and fracture toughness as calculated experimentally and by finite element method was found to be 5.74% and 7.69%, respectively, which is within the acceptable range.