Effect of white layer on the damping capacity of metal matrix composites

Damping is the materialʹs ability to dissipate elastic strain energy during mechanical vibration. Even though, damping measurements can be performed using different methods, dynamic mechanical analyzer is one of the best equipment used to find the damping capacity of metal matrix composites. In general, the samples for the damping measurements will be machined using the wire cut Electrical Discharge Machining (EDM) process to study the damping behavior. In the present work, the specimens for damping measurements were prepared by using the wire cut EDM process and the milling process and the results are compared. Damping measurements of all the specimens were measured by dynamic mechanical analyzer (DMA) at different frequencies in air atmosphere. It was observed that, the specimens machined using the wire cut EDM process exhibit lower damping values compared with milling machined specimens. The lower damping values for the wire cut EDM machined specimens are probably due to the formation of the white layer on the surface of the specimens.