MICROSTRUCTURALLY-BASED MODELING OF INTERGRANULAR CREEP FRACTURE USING GRAIN ELEMENTS

A new numerical method is proposed to simulate intergranular creep fra cture in large polycrystalline aggregates. The method utilizes so-call ed grain elements to represent the polycrystal. These grain elements t ake care of the average elastic and creep deformation of individual gr ains. Grain boundary processes, like cavitation and sliding, are accou nted for by grain boundary elements connecting the grains. Results are compared with full-field finite element calculations. The method is d emonstrated to capture the essential features of creep fracture, like creep constrained cavitation and the interlinkage of microcracks. Also the performance in polycrystals with random variations in microstruct ure, in terms of grain shape, is shown to be reasonably well. For the size of the unit-cell considered, a factor of around 600 is gained in computer time as compared with the full-field calculations. (C) 1997 E lsevier Science Ltd.