Abstract:Ni-Mn-Ga-X microwires were produced by melt-extraction technique on a large scale. Their shape memory effect, superelasticity, and damping capacity have been demonstrated. Here, the excellent magnetocaloric effect was revealed in Ni-Mn-Ga-Cu microwires produced by melt-extraction and subsequent annealing. The overlap of the martensitic and magnetic transformations, i.e., magnetostructural coupling, was achieved in the annealed microwires. The magnetostructural coupling and wide martensitic transformation tempe… Show more
“…8. Noteworthily, the RC eff of the present Co6 alloy reaches 223 J/kg, which is significantly larger than those of the stoichiometric Ni-Mn-based alloys 18,45,76,77,79,81–84 and is comparable to those of some Co-doped Mn-rich Ni-Mn-based compounds 1,63,78–80,83 . Besides, the achieved RC eff is also comparable to those rare-earth containing La(FeSi) 13 -based 72,73 and Gd 5 (SiGe) 4 -based 74,75 compounds.…”
Section: Resultsmentioning
confidence: 57%
“…Besides, the achieved RC eff is also comparable to those rare-earth containing La(FeSi) 13 -based 72,73 and Gd 5 (SiGe) 4 -based 74,75 compounds. Of note is that the working temperature of the present alloy is slightly above 300 K, which is very encouraging for room-temperature magnetic refrigeration applications.Figure 8Effective magnetic refrigeration capacity RC eff and working temperature span under a magnetic field of 5.0 T for the present Co6 alloy and some most studied magnetocaloric materials, such as La(FeSi) 13 -based 72,73 , Gd 5 (SiGe) 4 -based 74,75 , NiMn-based 1,18,45,63,76–84 compounds. These alloys were selected because their magnetocaloric effects (MCE) are all related to the first-order martensite transformation and are tested around the magnetostructural transition temperatures.…”
Section: Resultsmentioning
confidence: 69%
“…Effective magnetic refrigeration capacity RC eff and working temperature span under a magnetic field of 5.0 T for the present Co6 alloy and some most studied magnetocaloric materials, such as La(FeSi) 13 -based 72,73 , Gd 5 (SiGe) 4 -based 74,75 , NiMn-based 1,18,45,63,76–84 compounds. These alloys were selected because their magnetocaloric effects (MCE) are all related to the first-order martensite transformation and are tested around the magnetostructural transition temperatures.…”
Section: Resultsmentioning
confidence: 95%
“…Therefore, a more reasonable criterion for assessing the cooling efficiency, the effective refrigeration capacity ( RC eff ) defined as RC eff = RC- AHL , was adopted here. For comparison, the RC eff values under a field of 5.0 T for the present work and some most studied magnetocaloric materials 1,18,45,63,72–84 are summarized in Fig. 8.…”
High magnetocaloric refrigeration performance requires large magnetic entropy change ΔSM and broad working temperature span ΔTFWHM. A fourth element doping of Co in ternary Ni-Mn-Sn alloy may significantly enhance the saturation magnetization of the alloy and thus enhance the ΔSM. Here, the effects of Co-doping on the martensite transformation, magnetic properties and magnetocaloric effects (MCE) of quaternary Ni47−xMn43Sn10Cox (x = 0, 6, 11) alloys were investigated. The martensite transformation temperatures decrease while austenite Curie point increases with Co content increasing to x = 6 and 11, thus broadening the temperature window for a high magnetization austenite (13.5, 91.7 and 109.1 A·m2/kg for x = 0, 6 and 11, respectively). Two successive magnetostructural transformations (A → 10 M and A → 10 M + 6 M) occur in the alloy x = 6, which are responsible for the giant magnetic entropy change ΔSM = 29.5 J/kg·K, wide working temperature span ΔTFWHM = 14 K and large effective refrigeration capacity RCeff = 232 J/kg under a magnetic field of 5.0 T. These results suggest that Ni40.6Mn43.3Sn10.0Co6.1 alloy may act as a potential solid-state magnetic refrigerant working at room temperature.
“…8. Noteworthily, the RC eff of the present Co6 alloy reaches 223 J/kg, which is significantly larger than those of the stoichiometric Ni-Mn-based alloys 18,45,76,77,79,81–84 and is comparable to those of some Co-doped Mn-rich Ni-Mn-based compounds 1,63,78–80,83 . Besides, the achieved RC eff is also comparable to those rare-earth containing La(FeSi) 13 -based 72,73 and Gd 5 (SiGe) 4 -based 74,75 compounds.…”
Section: Resultsmentioning
confidence: 57%
“…Besides, the achieved RC eff is also comparable to those rare-earth containing La(FeSi) 13 -based 72,73 and Gd 5 (SiGe) 4 -based 74,75 compounds. Of note is that the working temperature of the present alloy is slightly above 300 K, which is very encouraging for room-temperature magnetic refrigeration applications.Figure 8Effective magnetic refrigeration capacity RC eff and working temperature span under a magnetic field of 5.0 T for the present Co6 alloy and some most studied magnetocaloric materials, such as La(FeSi) 13 -based 72,73 , Gd 5 (SiGe) 4 -based 74,75 , NiMn-based 1,18,45,63,76–84 compounds. These alloys were selected because their magnetocaloric effects (MCE) are all related to the first-order martensite transformation and are tested around the magnetostructural transition temperatures.…”
Section: Resultsmentioning
confidence: 69%
“…Effective magnetic refrigeration capacity RC eff and working temperature span under a magnetic field of 5.0 T for the present Co6 alloy and some most studied magnetocaloric materials, such as La(FeSi) 13 -based 72,73 , Gd 5 (SiGe) 4 -based 74,75 , NiMn-based 1,18,45,63,76–84 compounds. These alloys were selected because their magnetocaloric effects (MCE) are all related to the first-order martensite transformation and are tested around the magnetostructural transition temperatures.…”
Section: Resultsmentioning
confidence: 95%
“…Therefore, a more reasonable criterion for assessing the cooling efficiency, the effective refrigeration capacity ( RC eff ) defined as RC eff = RC- AHL , was adopted here. For comparison, the RC eff values under a field of 5.0 T for the present work and some most studied magnetocaloric materials 1,18,45,63,72–84 are summarized in Fig. 8.…”
High magnetocaloric refrigeration performance requires large magnetic entropy change ΔSM and broad working temperature span ΔTFWHM. A fourth element doping of Co in ternary Ni-Mn-Sn alloy may significantly enhance the saturation magnetization of the alloy and thus enhance the ΔSM. Here, the effects of Co-doping on the martensite transformation, magnetic properties and magnetocaloric effects (MCE) of quaternary Ni47−xMn43Sn10Cox (x = 0, 6, 11) alloys were investigated. The martensite transformation temperatures decrease while austenite Curie point increases with Co content increasing to x = 6 and 11, thus broadening the temperature window for a high magnetization austenite (13.5, 91.7 and 109.1 A·m2/kg for x = 0, 6 and 11, respectively). Two successive magnetostructural transformations (A → 10 M and A → 10 M + 6 M) occur in the alloy x = 6, which are responsible for the giant magnetic entropy change ΔSM = 29.5 J/kg·K, wide working temperature span ΔTFWHM = 14 K and large effective refrigeration capacity RCeff = 232 J/kg under a magnetic field of 5.0 T. These results suggest that Ni40.6Mn43.3Sn10.0Co6.1 alloy may act as a potential solid-state magnetic refrigerant working at room temperature.
“…12.7 J kg À1 K À1 . ÁS m in the present microwire exceeds that in many other magnetic microwires (Zhang et al, 2016b(Zhang et al, , 2017b. Our Ni 43.7 Cu 1.5 Co 5.1 Mn 36.7 In 13 microwire shows both a pronounced magnetic field-induced magnetostructural transformation and huge tensile superelasticity as a result of a stress-induced martensitic transformation.…”
Section: Magnetic Field-induced Magnetostructural Transition and Magnmentioning
Meta-magnetic shape-memory alloys combine ferroelastic order with ferromagnetic order and exhibit attractive multifunctional properties, but they are extremely brittle, showing hardly any tensile deformability, which impedes their practical application. Here, for the first time, an Ni–Cu–Co–Mn–In microwire has been developed that simultaneously exhibits a magnetic field-induced first-order meta-magnetic phase transition and huge tensile superelasticity. A temperature-dependent in situ synchrotron high-energy X-ray diffraction investigation reveals that the martensite of this Ni43.7Cu1.5Co5.1Mn36.7In13 microwire shows a monoclinic six-layered modulated structure and the austenite shows a cubic structure. This microwire exhibits an oligocrystalline structure with bamboo grains, which remarkably reduces the strain incompatibility during deformation and martensitic transformation. As a result, huge tensile superelasticity with a recoverable strain of 13% is achieved in the microwire. This huge tensile superelasticity is in agreement with our theoretical calculations based on the crystal structure and lattice correspondence of austenite and martensite and the crystallographic orientation of the grains. Owing to the large magnetization difference between austenite and martensite, a pronounced magnetic field-induced magnetostructural transition is achieved in the microwire, which could give rise to a variety of magnetically driven functional properties. For example, a large magnetocaloric effect with an isothermal entropy change of 12.7 J kg−1 K−1 (under 5 T) is obtained. The realization of magnetic-field- and tensile-stress-induced structural transformations in the microwire may pave the way for exploiting the multifunctional properties under the coupling of magnetic field and stress for applications in miniature multifunctional devices.
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