Functional components, driven by the martensitic transformation in Ti- and NiTi- based alloys, offer huge potential benefits to many engineering sectors. However, one of the key barriers to realising this potential has been the inability to tailor the transformation behaviour to specific operational conditions. This problems is exacerbated by an incomplete understanding of the role of alloying and microstructural condition, coupled with significant variations in corresponding literature data. This project seeks to address these issues by developing an enhanced mechanistic description of the transformation in a range of binary and ternary Ti- based alloys. Alloys will be fabricated by arc melting pure elements, processed by cold rolling and subjected to recrystallisation heat treatments. The resulting microstructural condition will be characterised by advanced electron microscopy whilst the crystallographic changes that occur during thermally and mechanically driven phase transformations will be studied using in situ synchrotron X-day diffraction.