Effect of Si on the partitioning of Mn between cementite and ferrite

ABSTRACT

The interlamellar spacings of pearlitic steels gradually increase as the isothermal transformation temperatures, correspondingly, the tensile strengths decrease, satisfying the Hall–Petch relationship. Si virtually completes its partitioning process during the eutectoid transformation. A depletion of Mn and an accumulation of Si are found in the concentration profiles of 0.95%-Si steel transformed at 793 K in the ferrite, but not in 0.22%-Si steel. It may attribute them to the Si–Mn diffusional flux couplings, which due to the strong interaction between Si and Mn atoms in the α-Fe. Transformation temperature increases to 873 K, a large amount of Mn atoms coming from ferrite cannot timely diffusion to cementite lamella core, forming a localised retention of Mn in the cementite phase side nearby the interface.

This is part of a thematic issue on Pearlitic Steel Wires.

KEYWORDS:

• Pearlitic steel
• partitioning
• atom probe tomography
• diffusion

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Linghui Huang http://orcid.org/0000-0002-3746-5552

Qi Zhang http://orcid.org/0000-0002-6925-1786

Additional information

Funding

This work was supported by the National Science Foundation of China (Nos. 51201031, 51371050, and 51301038) and the Fundamental Research Funds for the Central Universities.