An investigation of microstructural change of low alloy steel AISI 4150 by Seebeck coefficient
Keywords:
Seebeck coefficient, Low alloyed steel, Heat treatment, XRD, MicrostructureAbstract
Low alloyed steels, whose hardness can be modified by heat treatment, have been widely used in various applications. After heat treatment, they are normally destructively characterized and tested by many approaches via optical microscope and hardness testing. It is useful to develop a non-destructive method relating to its properties and microstructures. The proposed non-destructive approach in this study is the Seebeck coefficient measurement. The materials in this study were carbon steels AISI 4150 rod with a diameter of 1.3 cm and length of 3 cm. The specimens were heat-treated at 900ºC for 1 hour and were then cooled to room temperature in furnace and in various mediums: air, oil and water. In addition, one of the samples was cooled in salt bath at 350ºC for 1 hour and then cooled in water. X-ray diffractometry (XRD) and optical microscopy (OM) were used to characterize their crystal structures and microstructures, respectively. The Seebeck coefficient was measured relative to that of copper. The result indicated that the Seebeck coefficients of the treated samples are negative and their magnitudes are inversely related to hardness. The Seebeck coefficient also tends to be related to the crystal structure. Microstructure investigation, in addition, revealed that the magnitude of the Seebeck coefficient increases with a decrease of grain size. In conclusion, the Seebeck coefficient measurement could possibly be applied to study the microstructure of low alloyed steels.
Downloads
References
Blatt, F.J., Schroeder, P.A., Foiles, C.L. and Greig, D.L. 1976. Thermoelectric power of metals, New York : Plenum press : 310.
Mott, N.F. and Jones H. 1936. The theory of the properties of metals and alloys. New York: Dover Inc.
Kasap, S. 1996. Thermoelectric effects in metals: Thermocouples. (Online). Available: http://www.materials.usask.ca/samples/Th ermoelectric-Seebeck.pdf [September 9, 2009].
Brahmi, A. and Borrelly, R. 1997. Study of aluminium nitride precipitation in pure Fe-Al-N alloy by thermoelectric power measurements. Acta Mater. 45(5) : 1889-1897.
Lavaire, N., Merlin, J. and Sardoy, V. 2001. Study of ageing in strained ultra and extra low carbon steels by thermoelectric power measurement. Scr. Mater. 44(4) : 553-559.
Massardier, V., Lavaire, N., Soler, M. and Merlin, J. 2004. Comparison of the evaluation of the carbon content in solid solution in extramild steels by thermoelectric power and by internal friction. Scr. Mater. 50(12) : 1435-1439.
Caballero, F.G., Capdevila, C., Alvarez, L.F. and García de Andrés, C. 2004. Thermoelectric power studies on a martensitic stainless steel. Scr. Mater. 50(7) : 1061-1066.
Vedernikov M.V. 1969. The thermoelectric powers of transition metals at high temperature. Adv. Phys. 18(74) : 337-370.
Krauss, G. 1990. Steel: Heat treatment and processing principles. ASM international. Ohio : U.S. 78.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2017 Journal of Metals, Materials and Minerals
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Authors who publish in this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal.