The proposed experiment concerns the role of microstructure on the high temperature deformation behaviour of single crystal Ni-base superalloys. This class of material is of great industrial importance due to it role as the material for gas turbine engines due to the high temperature mechanical properties that they exhibit. The proposed experiment aims to characterise the influence of rafted (directionally coarsened) gamma prime precipitates in the microstructures compared to the as cast and homogenised microstructure of cubiodal precipitates in the gamma matrix on the high temperature creep behaviour at high applied loads. An in-situ thermomechanical loading experiment on ENGIN-X will allow for the characterisation of the elastic strain during creep loading (constant stress) at the typical operating temperature of turbine blades at 1000C as a function of microstructure.