MICROSTRUCTURES, HARDNESS AND IMPACT TOUGHNESS OF COMPOSITEE AZ91/SIC IN AUTOMOTIVE STRUCTURAL APPLICATIONS

Abstract

This paper presents the results of research and fabrication of AZ91/SiC compositee through casting method in a protective Ar atmosphere. The microscopic characteristics as well as the distribution of SiC particles in the AZ91 matrix were analyzed by field emission scanning electron microscopy (FESEM) and energy dispcrsive X-ray spectroscopy (EDS). The results show the distribution of SiC particles in the matrix phase and no reaction occurs between SiC and the molten Mg alloy during the synthesis. The hardness and impact toughness of AZ91/SiC compositees were evaluated and compared with unreinforced AZ91 alloy, aluminum alloy and steel. The results show that the AZ91/SiC composites with 15% by weight of SiC has a hardness value of 76 HRB, equivalent to steel commonly used in automotive structural applications and 130% increased impact toughness compared to the AZ91 alloy. While the density is much lighter than steel, this material has the potential to replace steel in automotive structural applications.