Investigation of small punch creep damage and rupture behavior in 347H stainless steel by means of experiments and a numerical simulation

The creep behavior of 347H stainless steel was investigated by small punch creep test (SPCT). Finite element simulations coupled with a strain damage model were employed to reveal the creep deformation mechanism of 347H stainless steel. The experimental results showed that the SPC curves of 347H stainless steel had a stagnation stage before the primary creep stage, and the duration of the accelerated stage of SPCT was shorter than that of uniaxial creep tests. The competition between precipitation strengthening and dislocation motion causes the deflection rate in the stagnation stage decreases first and then increases. A similar change of deflection rates was observed in the following creep stages, which can be attributed to the stress redistribution and crack propagation in the SPCT specimen. The present work provides a comprehensive understanding of the creep behavior and fracture mode of 347H stainless steel under multiaxial stress, and could promote the development of a new method for characterizing material properties through SPCT.