Shape memory properties of Cu-based thin tapes obtained by rapid solidification methods

Two different rapid solidification techniques were utilized to produce thin tapes of Cu-13Al-xNi-1Ti (wt.%, with x=5, 5.5, 6) shape memory alloys directly from the melt. Both melt-spinning and twin-roll casting (quenching between the gap of two rollers) have resulted successful methods to obtain ribbons (8 mm width, 55 mu m thickness) and strips (29-30 mm width, 450 mu m thickness) with grain sizes below 2 mu m, after optimization of the processing parameters. Although as a consequence of the rapid solidification the martensitic transformation temperatures are depressed, after annealing at 700 degrees C the high transition temperatures of the alloys in the bulk form are re-established. Measuring of length change under uniaxial tensile load shows elongations up to 1.8% (at 90 MPa) on cooling through the martensitic transformation. (c) 2006 Elsevier B.V. All rights reserved.