An analysis of creep deformation parameters. Part 2: experimental study

Loading Rate Effects on the Hydrogen Enhanced Cracking Behavior of Ni- and Co-based Superalloys for Marine Applications

“…In other words, if the dK/dt outpaces the H diffusion, the HEDE mechanism will decline and da/dtII will decrease with increasing dK/dt. This diffusion limited mechanism is proposed to be responsible for the retardation of EAC at high dK/dt loading rates [30], [36], [41], [79]. Clearly, the current data show the opposite trend of increasing da/dtend with increasing dK/dt (0.1 to 4 MPa√m) for Monel K-500, which suggests that at these loading rates the diffusion kinetics are sufficiently rapid to not be limiting the EAC.…”

“…Modern fracture mechanics testing approaches address these shortcomings to enable a more conservative and rigorous characterization of the EAC behavior by quantifying the crack growth rate, da/dt, and stress intensity, K, relationship of a wide range of stress intensity values. Such efforts were pioneered by Dietzel and Clark-Landes and initial attempts to codify such testing are reported in ISO/DIS7539-9 and in an augmented version of ASTM G129 [26], [30]. Recent efforts extend these approaches by using high fidelity direct current potential difference (dcPD) techniques to monitor the crack extension in real-time and feed these data into a software controlled loading system [4].…”