It is proposed that crack nucleation will be investigated at ISIS using the EnginX beam line with the IMAT imaging detector. Notched LCF specimens with varying materials and Kt factors will be used. Imaging will be combined with strain measurements to provide an insight into how different materials and Kt factors affect crack nucleation. This is of significant interest to industry when trying to improve the life of components.Aims and objectives:1) To investigate crack nucleation in selected superalloys by imaging crack nucleation and measuring strain around a notch during fatigue testing.2) To investigate which materials are notch sensitive and how this effects crack nucleation and strain distribution.