1995 Volume 36 Issue 5 Pages 632-638
The influence of deformation temperature on the Bauschinger effect (BE) of a high-strength TRIP-aided dual-phase (TDP) steel containing retained austenite particles of 10 vol% was investigated in a temperature range between 27 and 200°C.
The BE of the TDP steel depended significantly on the deformation temperature, although such a temperature dependence did not appear in a conventional ferrite-martensite dual-phase (DP) steel. Large BE, i.e., remarkable transitional softening and subsequent permanent softening proposed by Orowan, appeared at 100 and 200°C, at which the retained austenite particles were more resistant to the strain-induced martensite transformation (SIT) than those at 27°C. The Bauschinger stress obtained at 200°C was as high as that of the DP steel.
The retained austenite particles as a hard phase increased the Bauschinger stress. The SIT, however, was expected to lower the Bauschinger stress by the following reason. Expansion and shear strains resulting from the SIT reduced both internal stresses in the retained austenite islands and in the ferrite matrix.
