Microstructure and damping capacity of AA6061/graphite surface composites produced through friction stir processing. (August 2020)

• Record Type: Journal Article
• Authors: Venkateswara Reddy, K.; Bheekya Naik, R.; Rao, Golla Rama; Madhusudhan Reddy, G.; Arockia Kumar, R.
• Is Part Of: Composites communications. Volume 20(2020)
• Publication Date: 2020-08
• Subjects: Friction stir processing -- Surface composites -- Damping capacity -- Dynamic mechanical analyzer
• DOI: 10.1016/j.coco.2020.04.018
• Languages: English
• ISSNs: 2452-2139

Abstract

Abstract: The present study is to improve the damping properties of AA6061-T6 alloy by incorporating graphite (Gr) flakes through friction stir processing (FSP). The amount of graphite varied from 5 to 15 vol%. The distribution of graphite particles and the microstructure refinement were analysed using optical and electron microscopy. The grains were indistinguishable in the stirred zone. The hardness of the surface composites decreased with an increase of graphite fraction. The dynamic mechanical analyzer was used to analyze the damping capacity of specimens extracted from the stir zone. The frequency dependent and temperature dependent damping capacity of FSP-ed AA6061 and the surface composites were observed to be better than the base metal. Significantly, the damping capacity of composite with 15 vol% graphite was 3.5 times of base-metal's damping at 250 °C. Highlights: The damping of AA6061/graphite composites prepared by FSP is reported. 400% increase in room temperature damping by the addition of 15 vol% graphite. 3.5 times increase in damping at 250 °C by adding 15 vol% graphite. The grain refinement significantly improved high temperature damping. Results demonstrate friction stir processing is effective to improve damping.