Ni-Fe-Ga-Co is a promising system for magnetic shape memory alloy applications, due to its good ductility, mobile twin boundaries and high transformation temperatures. Unlike previous studies which focused on compositions with a Ga content of 27 at.%, here the martensitic transformation and magnetic
Formation and magnetic properties of butterfly-shaped martensite in an Fe–Ni–Cr alloy
✍ Scribed by S. Akturk; T.N. Durlu
- Publisher
- Elsevier Science
- Year
- 2006
- Tongue
- English
- Weight
- 566 KB
- Volume
- 438-440
- Category
- Article
- ISSN
- 0921-5093
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✦ Synopsis
The butterfly-shaped martensitic transformation has been examined by means of transmission electron microscope (TEM) and the magnetic properties of the alloy have been studied by using Mössbauer spectroscopy in an Fe-16.24%Ni-0.46%Cr (at.%) alloy. Mössbauer spectroscopy examinations showed that the austenite state is paramagnetic and butterfly martensite is ferromagnetic. The volume fraction changes, the effective hyperfine field of the ferromagnetic martensite phase and isomery shift values have also been determined by Mössbauer spectroscopy. In situ TEM studies were carried out in order to elucidate the nucleation and growth mechanisms of the martensite. The nucleation and growth of martensite is related to the motion of dislocations in austenite and this fact plays an important role in the kinetics of the martensitic transformation. Based on these experimental results, the nucleation and growth mechanisms of martensite crystals are discussed in detail.
📜 SIMILAR VOLUMES
Thermoelastic and strain-induced martensitic transformations of single crystalline Ni 49.7 Mn 29.1 Ga 21.2 magnetic shape memory alloys were investigated by simultaneous detection of the strain and magnetization. The transformation temperature to austenite was T A = 314 K. The thermoelastic transfor