Abstract: The investigation was
performed into the characteristics of the void growth at
different stress triaxiality levels during plastic deformations
using the axisymmetrical smooth and a series of
circumferencetially notched tensile specimens of a spheroidized
carbon steel. An expression for the least stress triaxiality
level, necessary to the lateral growth of voids, was derived
from the previous model D[(σm/σ)c]=0.5[1+(2exp1.5εp-1)-1] which
shows that, at some plastic strain, the void will start to
expand in the transverse direction when a critical stress triaxiality level is exceeded by that in the specimen. The
conclusion has been further verified by the experimental
observations. Moreover, it is proven that the higher the stress
triaxiality level, the lower the aspect ratio of voids during
plastic deformations, which causes the lateral coaescence of
voids to occur at a lower plastic strain level and leads to the
reduction of the material's ductility and toughness.
Key words:
Stress triaxiality Plastic
deformation Void growth
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