Microstructural Refinement and Strain Hardening Behavior in Low-Density Ultrafine Pearlite Steel

摘要

Advanced low-density steels that meet energy shortages and high safety requirements have become a hot research topic in materials science. The addition of light elements with medium-Al content (5 wt%) to ultrahigh-strength pearlite cable steel alloy reduces the material density and causes a microstructural change from traditional ?-pearlite (ferrite + cementite) to ?-pearlite and ?-pearlite (ferrite + cementite + ?-carbide). The results show that the moderate addition of Al and Mn (5 wt%) promotes the formation of ?-carbide, which inhibits the diffusion of C and significantly delays the eutectoid transformation process of pearlite. Meanwhile, the transformation free energy of pearlite increases and obviously refines the lamellar spacing of the ultrafine pearlite by ?-carbide. Simultaneously, the interaction between ?-carbides and dislocations is initiated, which increases the strain hardening rate of ultrafine pearlitic steel.

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