On the role of athermal and isothermal omega on the stress induced martensitic transformation in Ti-18Nb (at.%)

Metastable β Ti-Nb alloys have potential as biomedical implant materials due to a low elastic modulus and good biocompatibility. However, these alloys are susceptible to the ⍵ phase transformation, which significantly stiffens the alloy. Despite this, there is limited agreement within the literature whether the form of the ⍵ phase is important in governing subsequent mechanical response. Here, this work utilises synchrotron X-ray diffraction data to conclusively demonstrates that ⍵ iso significantly inhibits a mechanically driven martensitic transformation, whereas ⍵ ath is seen to have a much smaller effect. This work therefore has important consequences for the design of new transforming materials.