Influence of the Manufacturing Process on Hot Extruded Shape Memory Alloy Metal Matrix Composites

Continuous composite extrusion offers the possibility for manufacturing shape memory alloy metal matrix composites (SMA-MMC) with an actuator function. Due to an eccentric position of the SMA wires as well as the transformation stress caused by the suppressed shape memory effect, a bending moment can be generated during thermal activation. In this paper it is examined how the amount of necessary prestrain as well as the activation temperature influences the generated curvature of the specimens. The investigated actuator concept requires a sufficient bonding between matrix material and SMA wire to transfer the occurring stresses. For this reason, it is furthermore investigated how the process steps of stretching and subsequent thermal activation affect the quality of the bonding zone. Conventional NiTi wires (SM495) with a diameter of 1.5 mm are embedded in an aluminum AA6060 matrix for experimental investigation.