X-ray diffraction and Mossbauer spectroscopy studies of cementite dissolution in cold-drawn pearlitic steel

Chakraborty, J and Ghosh, M and Ranjan, Rajeev and Das, G and Das, D and Chandra, S (2013) X-ray diffraction and Mossbauer spectroscopy studies of cementite dissolution in cold-drawn pearlitic steel. In: PHILOSOPHICAL MAGAZINE, 93 (36). pp. 4598-4616.

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Abstract

Cementite dissolution in cold-drawn pearlitic steel (0.8 wt.% carbon) wires has been studied by quantitative X-ray diffraction (XRD) and Mossbauer spectroscopy up to drawing strain 1.4. Quantification of cementite-phase fraction by Rietveld analysis has confirmed more than 50% dissolution of cementite phase at drawing strain 1.4. It is found that the lattice parameter of the ferrite phase determined by Rietveld refinement procedure remains nearly unchanged even after cementite dissolution. This confirms that the carbon atoms released after cementite dissolution do not dissolve in the ferrite lattice as Fe-C interstitial solid solution. Detailed analysis of broadening of XRD line profiles for the ferrite phase shows high density of dislocations (approximate to 10(15)/m(2)) in the ferrite matrix at drawing strain 1.4. The results suggest a dominant role of 111 screw dislocations in the cementite dissolution process. Post-deformation heat treatment leads to partial annihilation of dislocations and restoration of cementite phase. Based on these experimental observations, further supplemented by TEM studies, we have suggested an alternative thermodynamic mechanism of the dissolution process.

Item Type:	Journal Article
Publication:	PHILOSOPHICAL MAGAZINE
Publisher:	TAYLOR & FRANCIS LTD
Keywords:	pearlitic steel; cementite dissolution; X-ray diffraction; Mossbauer spectroscopy; transmission electron microscopy
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	08 Jan 2014 06:00
Last Modified:	08 Jan 2014 06:00
URI:	http://eprints.iisc.ac.in/id/eprint/48149

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