Indian Journal of Science and Technology

Abstract

Objectives: The objective of the present study is to prepare Al6061-Gr-SiChybrid composites by stir casting route and the effect of Equal Channel Angular Pressing (ECAP) on the microstructure and mechanical properties of Al6061-Gr-SiC hybrid composites will be evaluated. Methods: In the present study, Al6061 is selected as matrix material. The reinforcement materials chosen are graphite (Gr) and Silicon carbide (SiC) particles of 10-30 µm size. The hybrid composites have been prepared by stir casting route in which the amount of Gr particles are kept at 3wt% and SiC particles are varied from 2-10wt% in steps of 2wt% . The cast hybrid composites are subjected to annealing treatment at 400o C for 4 hours and specimens have been prepared from these composites for ECAP process. The ECAP process was carried out at room temperature using a die with channel angle of 120o and Bc route was adopted for successive passes. The influence of ECAP on microstructure and mechanical properties of Al-Gr-SiC hybrid composite was evaluated. Findings: The microstructural study revealed that the composites are free from defects and also the distribution of reinforcement particles in the matrix are fairly uniform. Significant improvement in micro hardness and tensile strength was observed as the wt% of SiCp increases in as cast Al6061-Gr- SiC hybrid composites. After ECAP process, the size and distribution of the reinforcement particles are not changed but significant reduction in the grain size of the matrix alloy was observed. The micro hardness and tensile test results revealed that, there is a significant improvement in the micro hardness and the Ultimate tensile strength of ECAP processed hybrid composites. The enhancement in mechanical properties are mainly attributed to the grain refinement of the matrix alloy and strain hardening of hybrid composite materials by ECAP process. Applications: The ECAP process had a profound effect in enhancing the mechanical properties of hybrid composites. These composite materials have great impact in automobile, military and aerospace industries.
Keywords: Al6061, ECAP, Hybrid Composites, Mechanical properties, Stir Casting, Silicon Carbide