Author(s)

Belete Sirahbizu Yigezu, Manas Mohan Mahapatra, Pradeep Kumar Jha

Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, India.

This paper presents the results of the comparative study of as cast microstructures and mechanical properties viz yield strength, ultimate tensile strength, elastic modulus, percentage elongation, hardness, percentage porosity and fracture characteristic of 5 wt% SiC and Al₂O₃ particulate reinforced Al-4% Cu-2.5% Mg matrix composites. These composite materials were prepared through stir casting process. Quantitative metallographic techniques were utilized to determine the average grain size of particles. The microstructures and tensile fracture characteristic of the representative samples of the composites were examined using optical microscope (OM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) techniques. The experimental results demonstrate a fairly uniform distribution of 50.8 μm Al₂O₃ and 49.2 μm SiC spherical particles with some clustering in few areas. At the interfaces of Al2O3 and the matrix, MgO and MgAl2O4 were observed. Similarly, Al₄C₃ was formed at the interfaces between SiC and the matrix. The mechanical property test results revealed that, for the same weight percentage of reinforcement, Al-4% Cu-2.5% Mg/5 wt% SiC composite exhibit a 15.8%, 16.4%, 4.97% and 10.8% higher yield strength, ultimate tensile strength, elastic modulus, and hardness, respectively. On the other hand, even if some porosity was observed in the Al₂O₃ reinforced composite, the percentage elongation (ductility) was 31% higher than that of SiC rein-forced composite. The tensile specimen of SiC reinforced composite failed in a brittle fashion without neck formation, whereas the Al₂O₃ reinforced composite failed in a ductile fashion with noticeable neck formation.

Al₂O₃; Casting; Intermetalics; Metal Matrix Composites; Metallography; SiC

Sirahbizu Yigezu, B. , Mahapatra, M. and Jha, P. (2013) Influence of Reinforcement Type on Microstructure, Hardness, and Tensile Properties of an Aluminum Alloy Metal Matrix Composite. Journal of Minerals and Materials Characterization and Engineering, 1, 124-130. doi: 10.4236/jmmce.2013.14022.