Creep behaviour of a nickel-based single crystal superalloy at the dendritic scale using micro-tensile specimen
Résumé
Because of their resistance to high temperature creep and fatigue, single crystal superalloys are the most suitable materials for the design of high performance turbine blades. Processing of these alloys induces macroscopic heterogeneities, such as dendrites, whose size is comparable to the thickness of the thinnest blades walls. Mechanical behaviour of “bulk” commercial single crystal superalloys has been widely investigated. However, local high temperature creep behaviour hasn’t been characterised at the scale of microstructural and chemical heterogeneities until now. In the present study, differences in the g/g’ microstructure have been observed and correlated with chemical variation from dendritic cores to interdendritic regions. Furthermore, microtensile specimens, thinner than the size of dendritic motifs, were prepared and will be tested at 1100°C.