Neutron irradiation of Nickel alloys produces vacanciesdue to damage, and helium from decay of activationproducts within the solid matrix which accumulate ininter-and-intra granular bubbles. Bubble formationcontributes to dimensional changes and potentialdegradation of bulk material properties. The presence ofa large number of intergranular bubbles may contributeto a reduction in the intergranular fracture toughnessfrom a reduction of grain boundary contact. In this workwe investigate the time-evolution of intergranular heliumbubbles using the Included Phase Model (IPM), a novelmesoscale technique which describes the morphology ofinterfaces as a parametric surface. The IPM preserveskey features of phase-field type models with asignificantly reduced computational cost. The modelaccounts for vacancies and helium in the solid matrix andvoid phase. Transport of the species and evolution of thephases is driven by the minimization of the interfacialenergy, the energy of vacancies on the grain boundary,and the elastic energy of the surrounding matrix. Thecharacteristics of the simulated bubble populations arediscussed in relation to TEM results from irradiatedInconel X-750.
展开▼
