Micromechanisms of damage nucleation during contact deformation of columnar multilayer nitride coatings

Verma, Nisha and Cadambi, Sumanth and Jayaram, Vikram and Biswas, Sanjay Kumar (2012) Micromechanisms of damage nucleation during contact deformation of columnar multilayer nitride coatings. In: ACTA MATERIALIA, 60 (6-7). pp. 3063-3073.

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Abstract

In order to resolve some missing micromechanistic details regarding contact deformation in nitride multilayer coatings we report here observations from cross-sectional transmission electron microscopy and focused ion beam studies of the Vickers indentations on TiN/TiAlN multilayer films of various total thicknesses as well as bilayer periods. The study of damage induced by contact deformation in a nitride multilayer coating is complemented by stress calculated using an analytical model. Kinked boundaries of sliding columns give rise to cracks which propagate at an angle to the indentation axis under a combination of compressive and shear stresses. It is seen that multilayers provide more distributed columnar sliding, thereby reducing the stress intensity factor for shear cracking, while interfacial dislocations provide a stress relief mechanism by enabling lateral movement of material. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	ACTA MATERIALIA
Publisher:	Science Direct
Additional Information:	Copy right for this article belongs to Elsevier B V
Keywords:	TRANSMISSION ELECTRON-MICROSCOPY;THIN HARD FILMS;TIN COATINGS;SPHERICAL INDENTATION;TIN/TIALN COATINGS; NUMERICAL-ANALYSIS;MECHANISMS;MICROSTRUCTURE;DEPOSITION; FRACTURE
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	20 Jul 2012 09:25
Last Modified:	20 Jul 2012 09:25
URI:	http://eprints.iisc.ac.in/id/eprint/44630

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