Work Hardening and Flow Softening of γ-TiAl Containing Ni

Journal article, 2004

This paper presents the true stress-strain curves and data analyses of a Ni-containing TiAl and its reference alloy based on the isothermal compression tests at 1000 deg. C and 0.01-1.0 s-1 strain rates. The results show that the minor Ni addition makes the flow softening coming sooner and therefore significantly lowers the peak stress. Those effects in addition with a better balance between the work hardening and flow softening during hot deformation, improve the steady state flow behavior of TiAl. The Ni-influence mechanisms are also suggested based on the TEM observation of dislocation configurations and lamellar breakdown during the deformation.