Geometric flowcontrol of shear bands by suppression of viscous sliding

Sagapuram, Dinakar and Viswanathan, Koushik and Mahato, Anirban and Sundaram, Narayan K and M'Saoubi, Rachid and Trumble, Kevin P and Chandrasekar, Srinivasan (2016) Geometric flowcontrol of shear bands by suppression of viscous sliding. In: PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 472 (2192).

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Abstract

Shear banding is a plastic flow instability with highly undesirable consequences for metals processing. While band characteristics have been well studied, general methods to control shear bands are presently lacking. Here, we use high-speed imaging and micro-marker analysis of flow in cutting to reveal the common fundamental mechanism underlying shear banding in metals. The flow unfolds in two distinct phases: an initiation phase followed by a viscous sliding phase in which most of the straining occurs. We show that the second sliding phase is well described by a simple model of two identical fluids being sheared across their interface. The equivalent shear band viscosity computed by fitting the model to experimental displacement profiles is very close in value to typical liquid metal viscosities. The observation of similar displacement profiles across different metals shows that specific microstructure details do not affect the second phase. This also suggests that the principal role of the initiation phase is to generate a weak interface that is susceptible to localized deformation. Importantly, by constraining the sliding phase, we demonstrate a materialagnostic method-passive geometric flow control-that effects complete band suppression in systems which otherwise fail via shear banding.

Item Type:	Journal Article
Publication:	PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
Additional Information:	Copy right for this article belongs to the ROYAL SOC, 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	10 Feb 2017 10:12
Last Modified:	10 Feb 2017 10:12
URI:	http://eprints.iisc.ac.in/id/eprint/56224

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