Investigation on the Mechanical Properties of A356 Alloy Reinforced AlTiB/SiCp Composite by Semi-Solid Stir Casting Method

Abstract

Employing the semi-solid stir casting method to strengthen MMCs by SiCp particle was the simplest way in the casting process. The strength and toughness of a composite material can be obtained through a combination of the A356 / Al7Si composites and SiCp particle. The purpose of this study was to investigate the difference in the mechanical properties of Al7Si1Mg/SiCp and Al7Si1Mg1.5TiB/SiCp composites, as well as the changing effects on the extra level of SiCp particle. Al7Si was used as matrix strengthened by SiCp with the percentage variations of 10, 15, 20 wt%. The additional level of 1.5 wt% AlTiB aimed for increasing the matrix grain refinement. The semi-solid stir casting method was performed to spread the SiCp particles evenly in the liquid matrix. The results of the study were the tensile strength value of as much as 143 MPa or the increase of 22.16%. The biggest yield strength on the Al7Si1Mg1.5TiB/SiCp composite was averagely as much as 106 MPa. The highest impact toughness was averagely amounted to 4.74 J/mm2. The lowest porosity value was averagely 2.10%. The morphology of the composite between the reinforcing particle and the matrix was able to unite and to be dispersed evenly. The present study was conducted through density test, tensile test, impact test, microstructure test, and SEM.