Processing and Mechanical Characterization of Hybrid Syntactic Foams

Abstract

Syntactic foam is lightweight and damage tolerant closed cell porous composites synthesized by dispersing hollow spherical particle called micro balloons into the matrix. Syntactic foams are used as a core in sandwich composites. Syntactic foams are being used in a variety of applications so it’s necessary to understand and predict deformation and fracture behavior of such composites. The properties of syntactic foams can be altered by changing density and volume fraction of micro balloons. In this work, two different density glass micro balloons and fly ash cenosphere are hybridized in total filler fraction of 60% in the steps of 25%. The glass micro balloons/ fly ash cenosphere filled diglycidyl ether of bisphenol A epoxy matrix hybrid syntactic foams are prepared by the hand lay-up (Molding) method. The physical and mechanical characterization tests are done according to ASTM standards. The physical characterization parameter includes density and matrix porosity whereas, Tensile, Quasi-Static Compression, Flexural (3-Point Bending), Fracture Toughness (Mode I), Charpy Impact and Micro Vickers Hardness grouped as mechanical characterization parameters. Field Emission-Scanning Electron Microscopy was performed on fractured surfaces to find out deformation and fracture mechanisms associated with each loading condition. Specific tensile modulus, specific compressive modulus, fracture toughness, specific fracture toughness and micro Vickers hardness showed considerable improvement with the addition of fly ash cenosphere in hybrid syntactic foams due to density and hard alumina silicate composition. Entropy integrated grey relational analysis was performed to select the best composition of glass micro balloons and fly ash cenospheres. The result of present investigations suggests the possible use fly ash cenosphere in combination with glass micro balloons without much hindrance to its mechanical properties to address the issue of land pollution and can effectively make money out of it.