In order to study the cavitation characteristics of a 2.9 Ni-1.1 Cr Steel, specimens with two hardness levels were tested at 550℃ with the stress ranging from 155 to 195 MN/$m^2$. Quantitative analysis conducted include densitometry, and fractography after cryogenic separation.
The difference of hardness did not give considerably different rupture-life. However, density changes, and the area fractions of cavitated grain boundaries were larger in the specimens with the lower hardness level. Because of the difference of grain boundary energy and grain boundary normal stress, the cavity growth rate was different in each grain boundary, and fully cavitated and coalesced grain boundaries were found within the half of the rupture-life.
The result also showed that both the observed number and size of cavities were generally enhanced in the region of grain corners.
