Dislocation microstructures of single crystal ⟨001⟩ CMSX-4 specimens tensile tested at 700 and 1000°C

Two principal methods are used to derive constitutive equations for single crystal Ni-base superalloys: development of a creep potential according the Hill’s theory and the summarization of all activated slip systems: theoretically, the octahedral and the cubic slip system must be considered. An overview of dislocation structure evolution has been performed using transmission electron microscopy (TEM) techniques on 〈001〉-orientated CMSX-4 specimens after tensile tests. The aim of the applied conventional TEM methods was to provide with more details about the influence of temperature and deformation rate on the deformation behaviour of CMSX-4 nickel-base single crystal. A correlation of the γ'phase deformation mechanisms and associated mechanical responses for different tensile testing conditions has been done. With TEM methods the dislocation dipole identification as well as the stacking fault nature has been demonstrated.