Martensitic and magnetic transformations of Ni–Ga–Fe–Co ferromagnetic shape memory alloys

Thermal characteristics of Ni–Fe–Ga–Mn and Ni–Fe–Ga–Co ferromagnetic shape memory alloys

“…In both cases, the Curie temperature increases, the effect being stronger in the alloy where Ni is replaced by Co. These results are consistent with previous works [12,13]. (c) The L2 1 -B2 order-disorder transition temperatures are little affected by addition of Co, whereas an increase of w50 K with respect to the ternary alloy is observed in the alloy with Mn addition.…”

“…The effect of many different elements has been studied in the Ni-Mn-Ga alloys; however, much less information exists in the new FSMA families. For the Ni-Fe-Ga system, to our knowledge, only some results of the effect of Co, In, Ag and Mn exist in the literature [10][11][12][13][14][15][16][17][18]. The first two elements added to Ni-Fe-Ga alloys with a fixed proportion of the three initial constituents have opposite effects: indium causes a strong decrease of the martensitic transformation (MT) temperatures, T M [10], while Co increases these temperatures [11].…”

“…The first two elements added to Ni-Fe-Ga alloys with a fixed proportion of the three initial constituents have opposite effects: indium causes a strong decrease of the martensitic transformation (MT) temperatures, T M [10], while Co increases these temperatures [11]. The effect of the fourth element substituting partially one of the three constituents has also been analysed: Co substituting Ni causes a drop of T M temperatures and increase of the Curie point, T C , the opposite behaviour occurring when Co substitutes Fe (in this case, the change of T C is very small) [12,13]. Finally, when Co substitutes Ga, the MT temperatures increase, while substitution of 1 at% Ni by Ag practically does not affect the transformation temperatures [14].…”

Magnetoelastic Anomalies Exhibited by Ni–Fe(Co)–Ga Polycrystalline Ferromagnetic Shape Memory Alloy

“…3(b) is equal to about 0.1%. Notably, the sample presents a small amount of disordered fcc gammaphase 20,21) consistent with the precipitates observed in the optical microscopy image. The reflections of the gammaphase shown in Fig.…”

The effect of heat treatment on mechanisms of martensitic transformations in ferromagnetic Ni49Fe18Ga27Co6 single crystals

“…The Ni-Fe-Ga-(Сo) alloys possess reserve plasticity unlike the brittle Ni 2 MnGa alloys, and can be used in a variety of current technological applications [1]. The authors of [2,3] investigated the magnetic properties and characteristic temperatures of thermoelastic MTs in Ni-Fe-Ga-(Сo) polycrystals as a function of their chemical composition and heat treatment. It was shown that due to a changing content of Co and precipitation of particles of the γ(А1)-and γ′(L1 2 )-phases during annealing at the temperatures within 673-973 K, one can control the temperature of the onset M s and end M f of the direct and A s , A f reverse MTs, as well as the Curie temperature and other characteristics of the material.…”