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Using sea coral as a new bio-mass in processing of particle-filled polymer composites is very promising in the field of structural applications. In this study, waste cuttlebone was used as a filler material in epoxy composites. In general, cuttlebone particles derived from crushing and sieving were in aragonite polymorph form. In the present study, calcite polymorph form was obtained after heat treatment of cuttlebone particles at 400 C. Presence of polymorph form, elemental composition and thermal stability were confirmed with different characterization techniques. Composites were prepared with aragonite and calcite polymorph form cuttlebone particles and commercially available calcium carbonate as reinforcement in epoxy matrix. Tensile tests were carried out to determine the composites strength and compared with predefined theoretical models. Heat-treated cuttlebone reinforced epoxy composites showed higher tensile properties and better interaction between filler and matrix than other composites.

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In this paper, the macro and micro-mechanical fracture behavior was studied for aluminum (Al6061) alloy matrix, reinforced with various proportions of TiC particles such as 3wt%, 5wt% and 7wt%. The Al6061-TiC metal matrix composites were produced by stir casting method to ensure uniform distribution of the TiC particulates in the Al matrix. The compact tension (CT) specimens were machined according to ASTM E399 specifications to evaluate the fracture toughness for Al6061-TiC metal matrix composites. The CT specimens were machined for crack to width (a/W) ratio of 0.5 and thickness to width (B/W) ratios of 0.2 to 0.7 with an increment of 0.1. Load versus crack mouth opening displacement (CMOD) data was plotted to estimate stress intensity factor KQ for various thicknesses of the specimen. The fracture toughness KIC was obtained by plotting stress intensity factor versus thickness to width ratios of specimen data. The fracture toughness of these composites varied between 16.4-19.2 MPa√m. Scanning Electron Microscope (SEM) studies was made on the fractured surface of the specimens to understand the micro-mechanisms of failure involved in these composites. Void initiation is more significant in the matrix near the interface. The micro-cracks grow from these micro-voids and crack propagates by linking these micro cracks locating the crack path preferentially in the matrix adjacent to the interface indicating ductile fracture.

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