A model of duplex structure for short vapour-grown carbon fibres

Abstract

Vapour-grown carbon fibres are a type of short carbon fibres produced by a single-stage process. They are not yet commercially available but their cost/performance ratio is excellent owing to their unusual inner microstructure. Nevertheless, much effort will be needed to achieve a fibre of this type with sufficient length and strength to be used as a composite reinforcer in the future. In this work a routine production is shown that yields fibres grown without any influence from the substrate. Under these conditions, their tensile behaviour and fracture are different from current ex-PAN fibres. A simple model is proposed for the evaluation of their strength by a measurement of the thickness of the two different layers that constitute each fibre.