In order to investigate the growth mechanism of cavities in 2.9 Ni-1.1 Cr steel stresses by 155 MPa at 550℃, two computer models are used to simulate the continuous nucleation and growth of cavities in the grain boundary. One is similar to that of Raj and Ashby in which cavities nucleated at each time interval grow independent of the cavities nucleated at the other time intervals. To simulate the whole interaction of cavities, such as changes of cavity spacing with time, the other is a new model developed by assuming that the whole cavities redistribute in a periodic square array.
Results show that the cavity growth seems to be controlled by the diffusive growth mechanism in both models. The cavity size change with time and the time in which coalesced cavities are first found are more effectively simulated by a new model and appear in good agreement with the results of Cho's experiment Density changes with time derived from the new model also agree well with that of Cho's experimental results.
