Processing and Evaluation of Al6082 based Hybrid Matrix Composites for Fracture Toughness using Taguchi Method

Abstract

Conventional monolithic materials are limited in gaining a proper combination of toughness, hardness, density, stiffness and strength. Application of Metal Matrix Composites (MMC’s) in areas such as automotive, aerospace, marine etc. are the most promising materials and gaining extensive response in the present day scenario. These materials are economical with high performance comparatively. Fracture toughness is low when compared to metals; i.e., Metal Matrix Composites are most sought to be often used in typical applications. Evaluation of the plane strain fracture toughness using specimen geometries and notches by various researchers for the application of Linear Elastic Fracture Mechanics have been benchmarked[1,2,3,4,5,].In the present work, evaluation of fracture toughness of Al6082 based Al2O3/Al2SiO5 particulate composites are fabricated using stir casting method. Input parameters such as wt. % of Al2O3, stirring speed and stir time on the hardness, tensile strength, impact strength and fracture toughness of cast Al6082/Al2O3/Al2SiO5 composites is investigated by Taguchi method.Taguchi’s L9 orthogonal array shows wt. % of Al2O3 is a higher influential factor for experimental design. Three process parameters i.e. wt. % of Al2O3 (3, 6, 9), stirring speed (150, 200, 250 rpm) and stirring time (5, 10, 15 min) are used to fabricate samples of MMC’s comprising of each factor with 3 levels. Micro structural characterization via scanning electron microscope (SEM) is used to have a visual observation on distribution of Al2O3 particles in Al 6082 matrix. Rockwell hardness, tensile test as per ASTM standards, Impact test by charpy technique and single - edge notched beam (SENB) for fracture toughness was carried.