Microstructure and Mechanical Characterization of AA390 and Si3N4 Metal Matrix Composite Using Severe Plastic Deformation

B. Vennela; J. Suresh Kumar; K. Chinna Maddaiah; M. Ranjith Kumar

Abstract

Metal matrix composites (MMCs) have significant attention in recent years due to their potential for improved mechanical properties compared to conventional monolithic materials. This study focuses on the microstructure and mechanical characterization of a MMC comprising AA390 aluminum alloy reinforced with Si3N4 particles. The severe plastic deformation (SPD) process, Equal Channel Angular Pressing (ECAP), was employed to fabricate the composite with enhanced mechanical properties. The ECAP method was chosen as it allows for substantial grain refinement and homogenization of the composite material, potentially enhancing its mechanical properties. The study begins with the fabrication of the AA390/Si3N4 composite using an ultrasonic stir casting process, followed by the ECAP process. The microstructural evolution of the AA390/Si3N4 composite was investigated at different passes of the ECAP process. Scanning electron microscopy (SEM) and Optical microscopy were utilized to examine the dispersion and distribution of Si3N4 particles within the aluminum matrix. The mechanical characterization of the MMC was performed through a series of tests, including hardness, tensile, and wear tests. The results demonstrated a significant increase in hardness and tensile strength compared to the unreinforced AA390 alloy. This improvement can be attributed to the homogeneous dispersion of Si3N4 particles and the refinement of grain structure induced by the severe plastic deformation.

Abstract

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