Recoverable stress-induced martensitic transformation in a ferromagnetic CoNiAl alloy

Karaca, H.E.; Караман, И.; Lagoudas, Dimitris C.; Maier, Hans Jürgen; Chumlyakov, Yuriy

doi:10.1016/s1359-6462(03)00470-6

Cited by 95 publications

(81 citation statements)

References 30 publications

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“…Initial measurements on Co-Ni-Ga alloys show similar trends to Ni 2 MnGa alloys in both their dependence of martensitic transformation temperatures on electron concentration and saturation magnetization [2,5]. However, unlike Ni 2 MnGa alloys which are single phase over a large compositional range [6], recent phase equilibria investigations [3,4] have reported that Co 2 NiGa alloys with transformations near room temperature lie within a twophase field, similar to the Co-Ni-Al alloys [4,7,8]. This major difference in phase equilibria imposes significant limitations on the synthesis of single crystals as well as subsequent annealing and training of the martensitic transformation.…”

Section: Introductionmentioning

confidence: 81%

Phase Stability of Single Crystalline Co-Ni-Ga Shape Memory Alloy

2003

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Single crystals of Co 48 Ni 22 Ga 30 have been synthesized using a modified Bridgman method. The ability to solidify and retain single phase B2 austenite was found to depend not only on the starting composition and growth rate, but also the ability to maintain sufficiently high cooling rates to avoid the precipitation of a Corich FCC phase during post-solidification cooling. DSC measurements on the single crystal found the M s , M f , A s , and A f to be 35.7°C, -1.8°C, 34.1°C and 72.2°C, respectively. On subsequent heating the B2 phase was found to partially decompose into the Co-rich phase at temperatures exceeding 380°C. Decomposition of the single phase B2 phase was tracked by microstructural observation, DSC, powder diffraction and low temperature heat capacity measurement. Restoration of the crystal to single phase B2 austenite required annealing of the crystal at temperatures above 1125°C followed by rapid cooling. 22 Ga 30 have been synthesized using a modified Bridgman method. The ability to solidify and retain single phase B2 austenite was found to depend not only on the starting composition and growth rate, but also the ability to maintain sufficiently high cooling rates to avoid the precipitation of a Co-rich FCC phase during post-solidification cooling. DSC measurements on the single crystal found the M s , M f , A s , and A f to be 35.7°C, -1.8°C, 34.1°C and 72.2°C, respectively. On subsequent heating the B2 phase was found to partially decompose into the Co-rich phase at temperatures exceeding 380°C. Decomposition of the single phase B2 phase was tracked by microstructural observation, DSC, powder diffraction and low temperature heat capacity measurement. Restoration of the crystal to single phase B2 austenite required annealing of the crystal at temperatures above 1125°C followed by rapid cooling.

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Section: Introductionmentioning

confidence: 81%

Phase Stability of Single Crystalline Co-Ni-Ga Shape Memory Alloy

2003

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“…The combination of large MFIS coupled with the possibility of rapid response makes FSMAs suitable for a wide range of applications such as actuators and sensors. However, there are certain microstructural and magnetic requirements necessary to obtain large MFIS such as twin boundary mobility, high strength against dislocation formation, low volume change upon transformation, and high magnetic anisotropy energy [9][10]. Although Co-33at.%Ni-29at.%Al polycrystals satisfy the mechanical requirements to obtain MFIS as shown in our previous study [9], a detailed single crystal study is needed to reveal the martensitic transformation characteristics such as the orientation and temperature dependence of transformation strain.…”

Section: Ferromagnetic Shape Memory Alloys (Fsmas) Have Attracted Incmentioning

confidence: 96%

“…However, there are certain microstructural and magnetic requirements necessary to obtain large MFIS such as twin boundary mobility, high strength against dislocation formation, low volume change upon transformation, and high magnetic anisotropy energy [9][10]. Although Co-33at.%Ni-29at.%Al polycrystals satisfy the mechanical requirements to obtain MFIS as shown in our previous study [9], a detailed single crystal study is needed to reveal the martensitic transformation characteristics such as the orientation and temperature dependence of transformation strain. This understanding will be beneficial for the future investigations on the magneto-thermo-mechanical 1 behavior of CoNiAl alloys and to establish a link between single and polycrystalline behavior.…”

Section: Ferromagnetic Shape Memory Alloys (Fsmas) Have Attracted Incmentioning

confidence: 96%

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Compressive response of a single crystalline CoNiAl shape memory alloy

Karaca

2004

Scripta Materialia

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“…Xuan et al [20], on the other hand, reported that annealing of ribbons resulted in an increase in the reverse martensitic transition temperature (T A ) from 230 K (melt-spun) to 265 K (annealed at 1173 K). Concomitantly, the Curie temperature of the austenite T In addition to these well-investigated Ni-and Mn-based compounds, other FSMAs have been studied, i.e., Ni-Fe-Ga [21][22][23], Co-Ni-Al [24,25] and Co-Ni-Ga [26][27][28][29]. The Co-Ni-Ga Heusler system was intensively studied as a promising alternative to Ni-Mn-Ga alloys, especially for high-temperature shape memory device applications [30][31][32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Effects of Annealing on the Martensitic Transformation of Ni-Based Ferromagnetic Shape Memory Heusler Alloys and Nanoparticles

Fichtner

Wang

Levin

et al. 2015

Metals

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We report on the effects of annealing on the martensitic phase transformation in the Ni-based Heusler system: Mn 50 Ni 40 Sn 10 and Mn 50 Ni 41 Sn 9 powder and Co 50 Ni 21 Ga 32 nanoparticles. For the powdered Mn 50 Ni 40 Sn 10 and Mn 50 Ni 41 Sn 9 alloys, structural and magnetic measurements reveal that post-annealing decreases the martensitic transformation temperatures and increases the transition hysteresis. This might be associated with a release of stress in the Mn 50 Ni 40 Sn 10 and Mn 50 Ni 41 Sn 9 alloys during the annealing process. However, in the case of Co 50 Ni 21 Ga 32 nanoparticles, a reverse phenomenon is observed. X-ray diffraction analysis results reveal that the as-prepared Co 50 Ni 21 Ga 32 nanoparticles do not show a martensitic phase at room temperature. Post-annealing followed by ice quenching, however, is found to trigger the formation of the martensitic phase. The presence of the martensitic transition is attributed to annealing-induced particle growth and the stress introduced during quenching.

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Recoverable stress-induced martensitic transformation in a ferromagnetic CoNiAl alloy

Cited by 95 publications

References 30 publications

Phase Stability of Single Crystalline Co-Ni-Ga Shape Memory Alloy

Phase Stability of Single Crystalline Co-Ni-Ga Shape Memory Alloy

Compressive response of a single crystalline CoNiAl shape memory alloy

Effects of Annealing on the Martensitic Transformation of Ni-Based Ferromagnetic Shape Memory Heusler Alloys and Nanoparticles

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