Characteristics and properties of ultrafine microduplex structure in high carbon steel after warm deformation

Using a Gleeble-3500 simulator,the uniaxial warm compression deformation of high carbon steel with lamellar pearlite was performed and an ultrafine(α+θ) microduplex structure was successfully produced.The ultrafine(α+θ) microduplex structure was observed with SEM and TEM,and the microhardness of the microduplex structure was characterized.The results show that dynamic continuous recrystallization of the ferrite matrix occurred and the lamella cementite are spheroidized in the center of warm compressed specimen.With prolonging holding-time(0～1000s) after warm deformation,ultrafine ferrite grains and cementite particles grew up in a certain extent,and their size grew from 0.3μm and 0.1μm to 0.8μm and 0.3μm,respectively.With strain and strain rate increasing,the microhardness decreased due to different microstructure formed in the high carbon steel.