Experimental measurements of kinetics of creep cavity elimination by a
nnealing and compressive creep are reported for a 1.3Mn-0.5Mo-0.5Ni st
eel. Samples of the steel were crept to implant creep cavities in the
grain boundaries. The mean cavity size and spacing were obtained after
measuring approximately 200 cavities and used for theoretical sinteri
ng rate calculation. The samples were then annealed for 800h at 550-70
0-degrees-C and compressively crept for 400h under 59-235 MPa and at 5
50-600-degrees-C to make the cavities shrink, and the creep cavity sin
tering rates were monitored using the highly sensitive density measure
ment technique. The results showed that sintering rates under compress
ive creep are rapid and depend proportionally on compressive creep rat
es, whereas annealing causes only slight sintering. Two models of diff
usional and constrained cavity growth were applied for the calculation
of sintering rate, and it was shown that the sintering rates calculat
ed using the constrained cavity growth model coincides with the experi
mental data. This coincidence means that the contraction in the neighb
orhood of cavitied grain boundary due to the atom flow from grain boun
dary to cavity surface during sintering is costrained by the adjoining
grain, causes local tensile strain in the neighborhood, and decreases
the sintering rate drived by surface energy of creep cavity. Therefor
it was indicated that the local tensile strain must be removed by com
pressive creep in the adjoining grains for progressive sintering.