| Titre : | Microstructures and shape memory characteristics of dual-phase Co–Ni–Ga high-temperature shape memory alloys (2011) |
| Auteurs : | Yan Li, Auteur ; Yan Xin, Auteur ; Liang Chai, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Acta materialia (Vol. 58 N° 10, Juin 2010) |
| Article en page(s) : | pp. 3655–3663 |
| Note générale : | Métallurgie |
| Langues : | Anglais |
| Tags : | Co–Ni–Ga Dual phases Shape memory alloys Martensitic phase transformation Fracture |
| Résumé : | The influence of microstructure on mechanical properties and shape memory characteristics of Co–Ni–Ga high-temperature shape memory alloys were investigated in this study. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to detect the microstructures. We found that these alloys were composed of dual phases, a non-modulated tetragonal L10 martensite and a face-centered cubic (fcc) γ phase. The martensite was twinned and well self-accommodated. The γ phase was a Co-based solid solution with 30% lower hardness than martensite. Although the fracture mode was intergranular, the strength and plasticity of the alloys increased markedly with the increasing volume fraction of the γ phase. The presence of the γ phase in grain boundaries rather than in the martensite is favorable to shape memory recovery. This was revealed by the maximum shape recovery strain over 5.0% that was obtained in the Co46Ni25Ga29 alloy, with the γ phase formed mainly in grain boundaries. |
| DEWEY : | 669 |
| ISSN : | 1359-6454 |
| En ligne : | http://www.sciencedirect.com/science/article/pii/S1359645410001461 |
