To study the microstructural and mechanical behavior of a new microalloyed transformation–twinning
induced plasticity steel, the compression tests were conducted from 25 to 1000 1C. Five different
categories of true stress–true strain curve, exhibiting distinctive strain hardening/strain softening and
stress fluctuation, have been characterized in the range of deformation temperature. The experimental
steel exhibits the strength of about 1.28 GPa after straining to 0.6 along with an outstanding strain
hardening rate (2000 MPa) during compression at 25 1C. This excellent combination of mechanical
properties is attributed to the occurrence of strain-induced martensite transformation. The martensitic
transformation continues occurring up to temperatures as high as 150 1C, while mechanical twinning is
considered as the chief deformation mechanism in the temperature range of 150–600 1C. Furthermore, a
banded-like structure is observed in the temperature range of 600–1000 1C as a result of precipitate
formation. This banded structure is mainly composed of planar slip as well as deformation twins with
misorientation of about 591.