Fabrication and Investigation of Damping Properties of Nano Particulate Composites

Abstract

Nano particulate composites with Al-Si alloys (LM6 and LM25) as matrix and Multiwall Carbon Nanotube (MWNT) as reinforcement (0.25, 0.5, 0.75, 1.0 and 1.5 weight percentage) have been fabricated by powder metallurgy process. Damping specimens were prepared according to ASTM E 756-05 standard and the specimens were subjected to free vibration test to investigate the damping ratio and natural frequency. It is observed from the free vibration test data; both alloys (LM6 and LM25) have shown significant improvement in damping ratio, natural frequency and modulus when reinforced with 0.5 weight percentage of MWNT. Increase in weight percentage of MWNT beyond 0.5 leads to deterioration in damping ratio, natural frequency and modulus. This is due to agglomeration of reinforcement phase. The same has been observed in the morphological study using transmission electron microscopy (TEM). In this work an attempt has been made to also investigate the mechanical properties of the fabricated composites.