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Particle size and microstrain measurement in ADI alloysa)

Published online by Cambridge University Press:  05 March 2012

Jorge L. Garin,
Rodolfo L. Mannheim and
Marco A. Soto
Jorge L. Garin*
Affiliation:
Department of Metallurgical Engineering, Universidad de Santiago de Chile, Casilla 10233, Santiago, Chile
Rodolfo L. Mannheim
Affiliation:
Department of Metallurgical Engineering, Universidad de Santiago de Chile, Casilla 10233, Santiago, Chile
Marco A. Soto
Affiliation:
Department of Metallurgical Engineering, Universidad de Santiago de Chile, Casilla 10233, Santiago, Chile
*
b)Electronic mail: jgarin@lauca.usach.cl
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Abstract

In this study we deal with the determination of crystallite-size distribution and microstrain measurement in austempered ductile irons (ADI) subjected to cold deformation, by means of x-ray diffraction line broadening. The deformation process imposed on the material yields the formation of microstrain and crystallite size domains within each grain, which are somehow related to the mechanical behavior of the alloy. Three series of samples were cold-worked from 2.5% to 20.0% of thickness reduction in order to determine the domain size and microstrain induced in the material, in terms of the original thickness of the castings and the percentage of cold work. The x-ray diffraction line-broadening effects were analyzed by means of the Warren–Averbach method, which allowed the separation of size and strain parameters. The particle size distribution resulted in an average column length in the range of 15.7–24.9 nm in the ferrite phase, while the austenite phase showed values varying between 13.4 and 36.3 nm. On the other side, the overall root mean square strain varied from 0.000 85 to 0.003 93 for ferrite and from 0.000 65 to 0.004 38 for austenite. In all of the studied cases the average column length decreased with increasing deformation, while the initial thickness of the cast samples did not show any clear correlation with increasing deformation.

Keywords

crystallite size and microstrainaustempered ductile iron

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Type
Technical Articles
Information
Powder Diffraction , Volume 17 , Issue 2 , June 2002, pp. 119 - 124
Copyright
Copyright © Cambridge University Press 2005

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