Solid-solid transitions between crystals follow diffusive nucleation, or various diffusionless transitions, but these kinetics are difficult to predict and observe. Here we observed the rich kinetics of transitions from square lattices to triangular lattices in tunable colloidal thin films with single-particle dynamics by video microscopy. Applying a small pressure gradient in defect-free regio...

Exploration of new ferroic (ferroelectric, ferromagnetic or ferroelastic) materials continues to be a central theme in condensed matter physics and to drive advances in key areas of technology. Here, using thin-film composition spreads, we have mapped the functional phase diagram of the Ni-Mn-Ga system whose Heusler composition Ni(2)MnGa is a well known ferromagnetic shape-memory alloy. A chara...

Some of the most interesting and technologically important solid-solid transformations are the first-order diffusionless (martensitic) transformations that occur in certain ordered multi-atomic crystals. These include the reconstructive martensitic transformations, where no group-subgroup symmetry relationship exists between the phases, found in steel and ionic compounds such as CsCl. Additiona...

In this study the α′′ stress-induced martensitic transformation and damping behaviour of the superelastic β-Ti–25Ta–25Nb alloy are investigated by tensile tests at room temperature and by dynamic mechanical analysis (DMA) in tensile mode for different applied stresses. Tensile tests show a fully non-linear elastic domain and, consequently, a specific method is proposed to determine the elastic ...

The influence of grain constraint on the magnetic field levels required to complete the isothermal martensitic transformation in magnetic shape memory alloys has been demonstrated for a NiCoMnSn alloy, and the magnetocaloric performance of an optimally heat treated alloy was quantified. Ni45CoxMn45-xSn10 melt spun ribbons with x = 2, 4, 5, and 6 were characterized. The x = 5 sample was determin...

Martensitic transformations are diffusionless solid-to-solid phase transformations characterized by a rapid change of crystal structure, observed in metals, alloys, ceramics, and proteins. They come in two widely different classes. In steels, the transformation microstructure induced by quenching remains essentially unchanged upon subsequent loading or heating; the transformation is not reversi...

In this research, graphitization transformation of a commercial hypereutectoid steel called CK100 was studied by the dilatometric experiments at the range of 600 – 700 °C from prior martensitic structure. Also the effect of quenching media on the initial graphitization time and completion of transformation has been discussed. Also, graphitization transition from the different prior microstructu...