Embrittlement and Flow Localization in Reactor Structural Materials

Wu, Xianglin ; Pan, Xiao ; Stubbins, James

University of Illinois at Urbana-Champaign, Urbana, IL

关键词: Building Materials;    Plastics;    Alloys;    Embrittlement;    Forecasting;   

DOI  :  10.2172/892910
RP-ID  :  DOE/ID/14337-1
RP-ID  :  FG07-02ID14337
RP-ID  :  892910

美国|英语

来源: UNT Digital Library

【 摘 要 】

Many reactor components and structural members are made from metal alloys due, in large part, to their strength and ability to resist brittle fracture by plastic deformation. However, brittle fracture can occur when structural material cannot undergo extensive, or even limited, plastic deformation due to irradiation exposure. Certain irradiation conditions lead to the development of a damage microstructure where plastic flow is limited to very small volumes or regions of material, as opposed to the general plastic flow in unexposed materials. This process is referred to as flow localization or plastic instability. The true stress at the onset of necking is a constant regardless of the irradiation level. It is called 'critical stress' and this critical stress has strong temperature dependence. Interrupted tensile testes of 316L SS have been performed to investigate the microstructure evolution and competing mechanism between mechanic twinning and planar slip which are believed to be the controlling mechanism for flow localization. Deformation twinning is the major contribution of strain hardening and good ductility for low temperatures, and the activation of twinning system is determined by the critical twinning stress. Phases transform and texture analyses are also discussed in this study. Finite element analysis is carried out to complement the microstructural analysis and for the prediction of materaials performance with and without stress concentration and irradiation.