Effects of cerium addition on martensitic transformation and microstructure of Ti_49.3Ni_50.7 alloy

In order to study the effect of Cerium on martensitic transformation and microstructure of Ti_49.3Ni_50.7 alloy, a group of TiNiCe alloys with different content of Ce addition were prepared. The microstructure and the martensitic transformation behavior of TiNiCe ternary alloys were investigated by optical microscopy, scanning electron microscopy (SEM). X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results show that the microstructure of _49.3Ni_50.7 alloy is changed obviously by Ce addition, and there are many Ce-rich phases dispersing in the TiNi matrix. One step martensitic transformation due to B2 ↔ B19′ transformation occurs during the cooling and heating processes of the TiNiCe ternary alloys. The phase transformation temperatures increase remarkably when the content of Ce is less than 2 at%. However, when the content of Ce is further increasing, the phase transformation temperatures increase slowly and tend to stable.