A materials testing 2.0 framework for identifying creep parameters from full-field strain measurements of a notched specimen

The Materials Testing 2.0 (MT2.0) paradigm offers a promising alternative to conventional uniaxial testing by identifying constitutive parameters from a single heterogeneous test. However, its application to time-dependent deformation in structural alloys remains limited. This study proposes a practical framework to identify the Norton creep parameters of Inconel 718 at 650 °C using a single notched compact tension (C(T)) specimen. The framework couples high-temperature digital image correlation (HT-DIC) with a finite element model updating (FEMU) algorithm. A logarithmic objective function is employed to mitigate parameter coupling and facilitate stable convergence during nonlinear power-law inversion. The identified parameters successfully reproduce the steady-state creep response across a broad stress regime. This regime was explicitly isolated from the high-stress power-law breakdown domain. Conversely, in the low-stress regime, the persistence of primary transient creep within the limited dwell slightly overestimates local strain rates; this transient bias acts to elevate the creep coefficient A and slightly lower the stress exponent n relative to the true baseline. These findings demonstrate that the proposed single-specimen approach is a practical, effective method for characterizing steady-state creep properties across a broad stress range, provided the physical boundaries imposed by transient kinetics and high-stress mechanisms are carefully considered.