Intermetallics

Intermetallics 10 (2002) 361–369 www.elsevier.com/locate/intermet

A new method for fabricating SMA/CFRP smart hybrid composites
Ya Xua, K. Otsukaa,*, H. Yoshidaa, H. Nagaia, R. Oishia, H. Horikawab, T. Kishic a Smart Structure Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan b Furukawa Techno Material Co., Ltd, 5-1-8 Higashi-Yawata, Hiratsuka, Kanagawa 254-0016, Japan c National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan Received 19 November 2001; received in revised form 25 December 2001; accepted 10 January 2002

Abstract In order to suppress the microscopic mechanical damages in composite system, and thus to increase the reliability of carbon fiber reinforced plastics (CFRP), a smart composite SMA/CFRP is attracting much attention. In this application, the shape memory alloy (SMA) is expected to exert compressive stress to CFRP by reverse transformation upon heating after fabrication. However, one big problem in the fabrication process is that the curing temperature of the composite (130  C) far exceeds the reverse transformation temperatures of Ti–Ni alloys ( 70  C). This paper presents a new method to overcome this difficulty. The method consists of using heavily cold-worked wires to increase the reverse transformation temperatures, and of using flash electrical heating of the wires after fabrication in order to avoid damaging of the matrix around wires. By choosing the reduction of cold drawing and composition of TiNi alloys properly, it will be shown that the method is actually applicable without using special fixture jigs, which are necessary otherwise, to the fabrication of such smart composite as SMA/CFRP. # 2002 Elsevier Science Ltd. All rights reserved.
Keywords: A. Composites; B. Martensitic transformation; B. Shape-memory effects; C. Thermomechanical treatment

1. Introduction SMA smart hybrid composites, in which SMA