Isothermal Martensitic Transformations in an Aged Ni-Rich Ti–Ni Alloy Containing Coherent Ti<sub>3</sub>Ni<sub>4</sub> Particles

Abstract

The time dependence nature of B2 (ordered cubic) to R (trigonal) and R to B19′ (monoclinic) martensitic transformations in an aged Ni-rich Ti–Ni alloy was investigated by electrical resistivity measurements. Both B2 to R and R to B19′ transformations exhibit time dependence nature in the aged alloy containing coherent lenticular Ti3Ni4 precipitates with an average diameter of about 110 nm. However, the successive B2-R-B19′ isothermal transformation is not detected by electrical resistivity measurements. The isothermal R-B19′ transformation is visualized by in situ scanning electron microscopy (SEM) observations.