中國(guó)有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 11 No. 1 February 2001 |
stressed two way memory effect of CuAlNi single crystals
R. Stalmans3，J. van Humbeeck3
（1. School of Materials Science and Engineering, Harbin Institute of Technology,
Harbin 150001, P.R.China;
2. Foreign Affairs Office, Liaoning Institute of Technology,
Jinzhou 12001, P. R.China;
3. M. T. M., K. U. Leuven, de Croylaan 2, Heverlee, Belgium, 3001）
Abstract:Various training methods for two way memory effect (TWME) and stressed two way memory effect (STWME) were tried on Cu-13.4Al-4.0Ni (mass fraction, %) single crystals by applying tensile stress along 〈001〉 direction ofβ phase. Thetraining method of cooling with load can induce a lot of martensite prone to stabilize, thus cause large residual deformation, wide hysteresis and small TWME. Training with constant load can produce STWME larger than 8% with the least residual deformation. By training procedure of martensite reorientation below Mf followed by thermal cycling, the TWME is relatively large with very small residual deformation and with comparatively narrow hysteresis of two-way memory. The obtained two-way memory curve after such training is not a closed loop, and the obtained TWME is not stable. However, these can be improved by thermal cycling. Training with martensite reorientation below Mf and thermal cycling under relatively low constant stress throughout the whole training procedure is the optimum way of obtaining TWME, and more than 1.7% TWME can be obtained. The thermomechanical history of the sample has a pronounced effect on the training result. Thermomechanical cycling has a softening effect on martensite.
Key words: training; two way memory effect; stressed two way memory effect; Cu-Al-Ni single crystal
