Kriechen der teilchenverfestigten Typ-A-Legierung NiCr23Co12Mo

The presented work focuses on the creep mechanisms of the Ni-base alloy NiCr23Co12Mo (Alloy 617). The aim is to develop a physical-based, constitutive material model which can be used for the design of power plant components. Particle hardening and internal back stresses are quantitatively and qualitatively described based on the combination of the results from hot tensile tests and creep tests, as well as microstructural investigations. The particle hardening arises from the precipitation of secondary phases such as Cr-rich M23C6-carbides and the γ’-phase. The material model is implemented in the finite-element software ABAQUS via user-subroutine CREEP and can predict multiaxial creep deformation. As an example of application, the creep deformation of a thick-walled pipe for a future 700°C-power plant has been predicted by the FE-model. Complex component tests allow the appropriate validation of the material model