J. Phys. IV France 07 (1997) C5-543-C5-547
TWSME in Cu-Al-Ni Alloys Obtained by Stabilised Stress Induced MartensiteM. Gigla, J. Lelatko and H. Morawiec
University of Silesia, Institute of Physics and Chemistry of Metals, Katowice, Poland
The effect of deformation degree, temperature and time of ageing on the TWSME has been studied in polycrystalline and single-crystalline Cu-Al-Ni alloys. The results confirm that to obtain the best TWSME one needs to select the training parameters. The trained single crystals exhibit a lower TWSME than the polycrystalline alloys for the same training conditions. In the trained single crystals a single martensite variant has not been observed, but they showed a fewer variants than the untrained samples. The TEM studies of the trained samples exhibit a complex dislocation arrangements which interact with very thin induced plates of martensite. Ageing of the one of polycrystalline alloys caused precipitation of coherent γ2-phase particles. No precipitates were found in the second one and in the similarly trained single crystals although in these alloys a significant TWSME was observed. This means that the role of the γ2-phase particles presence to obtain the TWSME by ageing under stress is not that important as it has been suggested.
© EDP Sciences 1997