کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1448748 | 988682 | 2010 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Microstructures and shape memory characteristics of dual-phase Co–Ni–Ga high-temperature shape memory alloys Microstructures and shape memory characteristics of dual-phase Co–Ni–Ga high-temperature shape memory alloys](/preview/png/1448748.png)
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.
Journal: Acta Materialia - Volume 58, Issue 10, June 2010, Pages 3655–3663