Formation of (Ferrite+Cementite) Microduplex Structure by Warm Deformation in High Carbon Steels

Abstract:

The microstructure change by warm deformation in high-carbon steels with different initial ferrite (α) + cementite (θ) duplex microstructures has been examined. Three kinds of initial structures, i.e., pearlite, α+spheroidized θ and tempered martensite, were prepared using Fe-0.8C-2Mn and Fe-1.0C-1.4Cr alloys and compressed by 30-75% at 973K at a strain rate of 5x10-4 s-1. Equiaxed fine α grains, approximately 2μm in diameter and mostly bounded by high-angle boundaries, are formed with spheroidized θ by dynamic recrystallization during compression of the pearlite by 75%. When the (α+θ) duplex structure containing spheroidized θ was deformed, the original α grains become elongated and only subgrains are formed within them by dynamic recovery. For the tempered martensite, equiaxed α grains similar to those in the deformed pearlite were obtained after 50% compression. This indicates that the critical strain needed for the completion of dynamic recrystallization of α is smaller for the tempered martensite than for the other structures.

• Periodical: Materials Science Forum (Volumes 539-543)
• Pages: 155-160
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.539-543.155
• Online since: March 2007
• Authors: Tadashi Furuhara, Takuto Yamaguchi, Shoji Furimoto, Tadashi Maki
• Keywords: Dynamic Recrystallization (DRX), Grain Boundary, High-Carbon Steel, Microduplex Structure

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