A mechanistic study of the temperature dependence of the stress corrosion crack growth rate in SUS316 stainless steels exposed to PWR primary water

作者：Meisnar Martina; Vilalta Clemente Arantxa; Moody Michael; Arioka Koji; Lozano Perez Sergio

来源：Acta Materialia, 2016, 114: 15-24.

DOI：10.1016/j.actamat.2016.05.010

• Transmission electron microscopy (TEM)
• Transmission Kikuchi diffraction
• Stress-corrosion cracking
• Temperature dependence
• Crack propagation

Complementary analytical transmission electron microscopy (TEM) and transmission Kikuchi diffraction (TKD) were used to study the influence of temperature on the crack growth rate (CGR) in SUS316 stainless steels. An Arrhenius-type temperature dependence of the CGR has been observed between 250 degrees C and 320 degrees C. However, stress corrosion cracking (SCC) CGRS were found to decrease between 320 degrees C and 360 degrees C, which cannot be explained in terms of a single operating mechanism. High-resolution characterization has produced direct evidence that the SCC CGR in SUS316 is subjected to, at least, two rate-controlling processes: thermally activated diffusion and mechanical response to external stress and internal strain. While diffusion of metallic and non-metallic species at the crack flanks are enhanced at higher temperatures (350 degrees C and 360 degrees C), mechanical response-based mechanisms appear to dominate at lower temperatures (320 degrees C and 340 degrees C). Higher strain concentrations and dislocation densities around the crack tip were found at low temperature, potentially leading to accelerated crack growth and a peak in the CGR at 320 degrees C. It is suggested that phenomena occurring near the crack tip can be potentially very different at high and low temperatures.

• 出版日期2016-8-1