Grain-size dependence of the two-way shape memory effect obtained by stabilisation in Cu-Zn-Al crystals

Instead of cycling stress or temperature repeatedly through the transformation temperature, it is possible to obtain the two-way shape memory effect (TWME) by pre-ageing the martensite. Results are reported on the influence of the grain size on the magnitude of the TWME and on the work that can be done against an opposing force. The properties of aged Cu-Zn-Al crystals with three different grain sizes are compared, namely single crystals, fine-grained polycrystals obtained by adding grain refiners, and coarse-grained polycrystals without grain refiners as an intermediate case. The usefulness for technological applications of the TWME induced by ageing is discussed. (C) 2003 Elsevier B.V. All rights reserved.