Year: 2004
Type: conference-paper
Abstract: Residual stresses in the dendritic structure of single-crystal nickelbase superalloys were investigated.Dilatometric measurements showed that the thermal contraction of the dendrite arms (DAs) is larger than that of the interdendritic regions (IRs).The reason is, that the ' phase, precipitating during cooling, has a smaller lattice parameter than the -matrix and that this ' misfit is higher in the DA than in the IR.In the "DA-IR-compound" the different thermal contractions cause residual stresses.The stress distribution within the dendritic cell was analyzed theoretically by finite element (FE) modeling.The stresses were proved directly by X-ray diffraction (XRD) and indirectly by the transformation of the ' morphology observed after load free annealing.It was found that dendritic stresses influence the structural and mechanical behavior of superalloys during high temperature creep: rafting and plastic deformation start in the primary dendrite arms (PDA).
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W2124197259