腐食疲労き裂成長に及ぼす力学的因子の役割

概要

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he role of mechanical factors in environmentally enhanced crack growth under cyclic loading was examined from a mechanistic view point in terms of time base crack growth rate in inert environment, [da/dt] _<inert>, which was clarified to reflect the crack tip strain rate directly. Corrosion fatigue crack growth rate data in a simulated BWR environment at different stress ratios were compared with those obtained by the slow strain rate test (SSRT), aiming the direct correspondence on the growth rate diagram, [da/dt]_E-[da/dt]_<inert> diagram. This diagram can be used to develope the mechanistically-based design rule for environmentally enhanced crack growth such as corrosion fatigue, stress corrosion cracking and slow strain rate tests on the pressure boundary materials in LWR environments. Furthermore, it provides a physical basis to understand the acceleration mechanism and also a useful tool to predict the maximum acceleration under conceivable operating conditions. Finally, the usefulness of SSRT coupled with fracture mechanics is emphasized from its applicability to predictive testing and toughness evaluation in terms of J_<Ic> or tearing modulus T_<mat> in aggresive environments.
社団法人日本材料学会の論文
1982-07-15