Thermal analysis of Mn 50 Ni 50−x (Sn, In) x Heusler shape memory alloys

Off-stoichiometry Heusler ribbons with nominal compositions of Mn50Ni50−x(Sn, In)x (x = 6, 8 and 10 at.%) has been produced by melt spinning. Thermal and thermodynamic analyses have been performed by means of differential scanning calorimetry scans of the reversible martensitic structural transformation. The transformation temperatures decrease as increasing In or Sn content. The entropy increases with increasing Sn or In content. The dissipation term of entropy is lower than 0.02 in all samples. The martensitic transformation (from austenite to modulated monoclinic 14M martensitic phase) was detected in Mn50Ni50−xSnx (x = 6, 8 and 10 at.%) and Mn50Ni50−xInx (x = 6 and 8 at.%) samples. The structural transformation was not detected in the alloy with 10 at.% of indium.