Creep cavity nucleation and growth in 12Cr–Mo–V steel

Abstract

Quantitative measurements of the number of cavities per unit area, mean cavity size, and cavitated area fraction are carried out on creep tested specimens of a 12Cr–Mo–V martensitic steel. Both interrupted and ruptured specimens are included. Cavities initiate at an early stage of tests. The number of cavities, mean cavity size, and cavitated area fraction exhibit a continued increase with increasing strain and time. At rupture, the number of cavities is about 30 000 mm−2, and the mean cavity size has a maximum value of about 2·5 μm.The cavitated area fraction is approximately 0·1% at 1% strain, 0·5% at 2% strain, and 10% at rupture. Cavity initiation and growth are analysed regarding temperature, stress, strain, and strain rate. A constrained cavity growth model is discussed and compared with the experimental results.MST/3097