Affiliation: | 1 A.F. Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg, Russia 2 Katholieke Universiteit Leuven, Departement MTM, De Croylaan 2, B-3001, Heverlee, Belgium 3 Insitut Génie Atomique, Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland 4 University of Antwerpen (RUCA), IMS, Middelheimlaan 1, B-2020, Antwerpen, Belgium |
Abstract: | 1. The present results indicate that the stress-induced β1→γ1′ martensitic transformation occurs for an impact duration of 2 × 10?6 s. This time interval appears to be sufficient also for the subsequent deformation of the γ1′ martensitic phase to occur.2. A structure memory effect has been found: Cu-Al-Ni austenitic crystals, shock-loaded at room temperature to induce γ1′–martensite, recall during subsequent temperature-induced martensitic transformation the martensitic variant structure (elastic properties) formed under the shock loading.3. Elastic properties of quenched β1′ and γ1′ crystals of the Cu-Al-Ni system are extremely sensitive to the shock-wave loading. Mechanisms of these effects, as well as of the structure memory effect, include the generation of internal stresses due to the high elastic anisotropy of the martensitic phases. These internal stresses either change the distribution of martensitic variants or govern the formation of the martensitic variant structure during the temperature-induced martensitic transformation. The generation of high internal stresses by impact loading of the β1′ martensitic phase is also detected by several anelastic phenomena.4. In contrast to elastic and anelastic properties, transformation temperatures are insensitive to the impact loading, pointing to the difference of structural elements responsible for the anelastic effects and for the interval and hysteresis of the thermoelastic martensitic transformation. |