|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Environmentally Assisted Cracking: Theory and Practice
||The Effects of Grain Boundary Structure on the Intergranular Stress Corrosion Cracking Initiation Susceptibility of Alloy 690 in High Temperature Water
||Wenjun Kuang, Gary Was
|On-Site Speaker (Planned)
Intergranular stress corrosion cracking (SCC) of alloy 690 in simulated pressurized water reactor primary environment is a result of a series of degradation processes such as outward diffusion of Cr, formation of surface chromia film, breakdown of surface film and intergranular oxidation. Those degradation processes are highly dependent on the grain boundary structure. In this work, the microstructures of twin boundaries and random high angle boundaries (RHABs) in alloy 690 after slow strain rate tensile testing in 360 oC hydrogenated water were studied. It was found that thin layers of chromia oxide form along twin boundaries and maintain strict orientation relationship with the neighboring grain matrixes. At RHABs, grain boundary migration is accompanied by formation of an intergranular oxide composed of NiO and chromia. The difference in SCC initiation susceptibility between twin boundaries and RHABs is discussed in relation to the different microstructures after degradation of grain boundaries.
||Planned: Supplemental Proceedings volume