The aim of this experiment is to study the effect of Aluminium (Al) on deformation mechanisms in Titanium (Ti) alloys with a particular emphasis on studying twinning. Titanium alloys are used by the aerospace industry due to their outstanding strength to weight ratio. In order to develop new high strength Ti alloys in the future, a much improved understanding of the effect of alloying elements on deformation mechanisms such as twinning is highly desirable. While Aluminium is often considered to reduce twining activity in Ti alloys, it is in fact relatively unclear if Al reduces either twin nucleation or twin growth or even both. The proposed in-situ loading experiments on ENGIN-X aim at determining twin evolution during loading and to shed light on the nucleation criteria and the role of Aluminium on twinning. The results will be interpreted using crystal plasticity modelling.