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Deformation mechanisms and texture evolution of in-situ magnesium matrix composites containing polymer derived SiCNO dispersoids during hot compression

Chelliah, Nagaraj M and Padaikathan, Pambannan and Surappa, M K (2018) Deformation mechanisms and texture evolution of in-situ magnesium matrix composites containing polymer derived SiCNO dispersoids during hot compression. In: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 720 . pp. 49-59.

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Official URL: http://dx.doi.org/10.1016/j.msea.2018.02.023

Abstract

In-situ magnesium matrix composite was fabricated by injecting a liquid polymer directly into, and having it converted into 2.5 vol% SiCNO ceramic dispersoids, within molten Mg using a stir-casting method. The deformation mechanisms and texture evolution for these as-cast composites were investigated in a strain rate range of 10(-3) - 1 s(-1) within a temperature range of 150-350 degrees C under uniaxial compression. It was observed that the deformed composites follow a power-law creep having a stress exponent, n = 8 and activation energy, Q = 149 kJ mol(-1) which suggest that deformation mechanism is controlled by lattice self-diffusion for constant structure creep. It was found that in the range of 150-250 degrees C, with a ratio of rate of work-softening to rate of work-hardening of about 0.80, twinning induced shear bands nucleate and propagate along the direction of maximum shear stress. When the temperature approaches 350 degrees C, the plastic flow is dominated by dislocation assisted slip. Analysis of Zener-Hollomon parameter (Z) revealed that the transition from twinning into dislocation slip dominated deformation progresses at 10(13) s(-1) < Z < 10(13) s(-1). Macro-textural studies confirm that while basal plane assists deformation by twinning mechanism, the non-basal prismatic planes favor significant plastic deformation by dislocation assisted slip for the in-situ composites.

Item Type: Journal Article
Additional Information: Copy right for this article belong to ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Id for Latest eprints
Date Deposited: 04 May 2018 19:41
Last Modified: 04 May 2018 19:41
URI: http://eprints.iisc.ac.in/id/eprint/59767

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