Влияние температуры деформации осадкой на формирование мелкозернистой структуры литого сплава системы Ni-Mn-Ga

Phonon softening in Ni-Mn-Ga alloys

The TA2 phonon dispersion curves of Ni-Mn-Ga alloys with different compositions which transform to different martensitic structures have been measured over a broad temperature range covering both paramagnetic and ferromagnetic phases. The branches show an anomaly (dip) at a wave number that depends on the particular martensitic structure, and there is softening of these anomalous phonons with d...

Влияние Магнетизма На Регенерацию Effect of Magnetism on Regeneration

Ferromagnetic shape memory alloys: Alternatives to Ni–Mn–Ga

This paper intends to review the state-of-the-art in the field of ferromagnetic shape memory alloys different than Ni–Mn–Ga, developed in the ast years. It starts with the effects of additions of different fourth elements to Ni–Mn–Ga and continues with the review of other Heusler (or B2) i-based and Co-based alloy systems, like Ni–Mn–X, Ni–Fe–Ga, Co–Ni–Al and Co–Ni–Ga alloys. Finally, ferromagn...

Role of Shuffles and Atomic Disorder in Ni-mn-ga

We report results of ab-initio calculations of the ferromagnetic Heusler alloy Ni-Mn-Ga. Particular emphasis is placed on the stability of the low temperature tetragonal structure with c/a = 0.94. This structure cannot be derived from the parent L21 structure by a simple homogeneous strain associated with the soft elastic constant C ′. In order to stabilise the tetragonal phase, one has to take...

Elastic constants of Ni-Mn-Ga magnetic shape memory alloys

We have measured the adiabatic second order elastic constants of two Ni-Mn-Ga magnetic shape memory crystals with different martensitic transition temperatures, using ultrasonic methods. The temperature dependence of the elastic constants has been followed across the ferromagnetic transition and down to the martensitic transition temperature. Within experimental errors no noticeable change in a...