Study of Mechanical Properties and Thermal Conductivity of Carbon and Basalt Fibre-Reinforced Hybrid Polymer Composites

Abstract

The objective of the present work is to investigate the mechanical properties, viz., tensile strength and hardness, and thermal conductivity properties of eight varieties of carbon–basalt hybrid composites, and analyse the microstructure of the hybrid composite with highest tensile strength using Scanning Electron Microscopy (SEM). In this work, carbon and basalt fibre-reinforced hybrid composites are produced through vacuum bagging technique using epoxy resin as the matrix. The hybrid composites are prepared in different fibre stacking sequences satisfying the predetermined volume percentages of carbon and basalt. In each sequence, 90/45 quasi-isotropic fibre orientations are used. The eight volume percentage combinations of Carbon (C) and Basalt (B) considered in the study are (0:100), (20:80), (40:60), and (50:50) with carbon fibres in 450 orientation, (50:50) with basalt fibres in 450 orientation, (60:40), (80:20), and (100:0). The stacking sequences of the aforesaid eight hybrid composites, respectively, are (B-B-B-B-B-B-B-B-B-B), (B-B-B-C-B-B-C-B-B-B), (B-B-C-C-B-B-C-C-B-B), (C-B-C-B-C-B-C-B-C-B), (B-C-B-C-B-C-B-C-B-C), (C-C-B-B-C-C-B-B-C-C), (C-C-C-B-C-C-B-C-C-C), and (C-C-C-C-C-C-C-C-C-C). It is observed from the results that the average values of tensile strength, hardness, and thermal conductivity are high, respectively, for (50:50) carbon–basalt hybrid composite with basalt fibres in 450 orientation and stacking sequence (C-B-C-B-C-B-C-B-C-B), (80:20) hybrid composite with stacking sequence (C-C-C-B-C-C-B-C-C-C), and (40:60) hybrid composite with stacking sequence (B-B-C-C-B-B-C-C-B-B). Finally, the SEM analysis of fractured tensile specimen of (50:50) hybrid composite with the stacking sequence (C-B-C-B-C-B-C-B-C-B) reveals that the matrix cracking, fibre breakage, de-bonding, and delamination between fibres and matrix plays an important role, and they are dominant fracture mechanisms.