Martensitic phase transformation in Ni-rich NiTi single crystals with one family of Ni4Ti3 precipitates

Compression-aging treatments tests were carried out with single crystals in order to nucleate precipitates under a compression stress in the [1 1 1] direction, conditions which favor the formation of a single family of Ni4Ti3 precipitates. The precipitation behavior under this type of stress-assisted aging is investigated. An attempt is made to study the effects of aging on the characteristics of the martensitic transformations. The objective of the present study is to lay the groundwork for investigating the characteristics of martensitic transformations in Ni-rich NiTi alloys by excluding effects associated with heterogeneous nucleation on grain boundaries in polycrystals.