Cross wedge rolling of a Ti6Al4V (ELI) alloy: the experimental studies and the finite element simulation of the deformation and failure
Abstract
The cross wedge rolling (CWR) deformation and
fracture of a Ti6Al4Al (ELI) alloy were investigated experimentally
and numerically using a coupled thermomechanical
finite element model analysis. The experimentally
determined flow stress and damage model parameters
were verified by tension split Hopkinson pressure bar testing
of notched samples. The simulation and experimental
CWR forces showed well agreements except near the end of
the stretching zone. The model analysis showed that the
temperature distribution in the work piece was nonuniform
during the CWR. When the initial temperature of
the work piece was relatively low, the work piece temperature
increased, a heating effect of the plastic deformation,
while relatively high initial work piece temperatures
resulted in cooling the work piece, caused by the work piece
contact with the tools. The cracks were shown numerically
to initiate in the midsections of the work piece during the
guiding action and elongated in a direction normal to the
maximum tensile stress triaxiality, resulting in cruciformshaped
crack formation, which was well agreed with the
previously observed crack shape.
