Internal friction was measured in 2 non-stoichiometric Ni2MnGa alloys. Several internal friction peaks which were attributed to some restructuring of the martensitic lattice were observed below Ms. From the strain dependence of internal friction, the activation enthalpy for movement of twin boundaries between martensitic domains was estimated to be equal to between 0.02 and 0.04eV.
Martensitic Transformations and Mobility of Twin Boundaries in Ni2MnGa Alloys Studied by Using Internal Friction. V.G.Gavriljuk, O.Söderberg, V.V.Bliznuk, N.I.Glavatska, V.K.Lindroos: Scripta Materialia, 2003, 49[8], 803-9
Table 10
Grain-Boundary Diffusivity of 51Cr in Ni-16.24Cr-6.78Fe-0.004wt%C
Temperature (K) | δD (m3/s) |
1346 | 6.1 x 10-20 |
1173 | 5.4 x 10-21 |
1113 | 1.4 x 10-21 |
1073 | 4.8 x 10-22 |
973 | 5.5 x 10-23 |
894 | 6.6 x 10-24 |