Tailored processing of epoxy with embedded shape memory alloy wires

Abstract

We present the development of a low-temperature liquid composite moulding cure schedulethat is compatible with the fabrication of shape memory alloy (SMA)–epoxy compositematerials. With this process, the SMA wires do not need to be maintained in place with anexternal frame, even though the peak post-cure temperature exceeds the activationtemperature of the SMA wires. The intrinsic interfacial shear strength of the final materialis experimentally determined from single wire pull-out tests, and is compared with theshear stress exerted at the interface by an activated SMA wire. These measurementsshow that the interface is strong enough to withstand the maximum activationstress. This is confirmed through tests involving the cyclic activation of SMA wiresembedded in epoxy samples. The paper successfully demonstrates that, by carefultailoring of the processing schedule, an SMA–epoxy composite that maintains astrong interfacial bond during both processing and subsequent activation of theembedded wires can be fabricated using standard composite processing methods.