TU Darmstadt / ULB / TUbiblio

Study on the deformation mechanics of hard brittle coatings on ductile substrates using in-situ tensile testing and cohesive zone FEM modeling

Rehman, H. U. and Ahmed, F. and Schmid, Christoph and Schaufler, J. and Durst, Karsten (2012):
Study on the deformation mechanics of hard brittle coatings on ductile substrates using in-situ tensile testing and cohesive zone FEM modeling.
In: Surface and Coatings Technology, Elsevier Science Publishing Company, pp. 163-169, 207, ISSN 02578972, DOI: 10.1016/j.surfcoat.2012.06.049, [Article]

Abstract

In the present work, the mechanics of the stress transfer from a ductile substrate to a brittle coating and the failure of coating segments by normal cracking and delamination are studied using in-situ tensile testing and cohesive zone finite element modeling. The in-situ tensile tests were performed in a scanning electron microscope (SEM) on a diamond coated Ti-substrate and hydrogenated amorphous carbon (a-C:H) coatings on two different steel substrates, with different work hardening behavior. These brittle coatings form cracked coating segments during the in-situ tensile test. The stress transfer from the substrate to the coating segments is dependent on the elastic and elastic/plastic properties of coating and substrate. Furthermore, the segmentation of the coating together with the delamination depends strongly on the film and substrate properties. Using cohesive zone finite element modeling, the influence of substrate and coating properties on the stress transfer, segmentation of the films and on the delamination is discussed. It was found that the saturation in spacing of the cracked coating segments is either cause by a localization of the plastic strain in the substrate or by a delamination of the coating segments. Delamination only occurs, when the flow stress of the substrate is about ~ 3 times larger than the interfacial shear strength.

Item Type: Article
Erschienen: 2012
Creators: Rehman, H. U. and Ahmed, F. and Schmid, Christoph and Schaufler, J. and Durst, Karsten
Title: Study on the deformation mechanics of hard brittle coatings on ductile substrates using in-situ tensile testing and cohesive zone FEM modeling
Language: English
Abstract:

In the present work, the mechanics of the stress transfer from a ductile substrate to a brittle coating and the failure of coating segments by normal cracking and delamination are studied using in-situ tensile testing and cohesive zone finite element modeling. The in-situ tensile tests were performed in a scanning electron microscope (SEM) on a diamond coated Ti-substrate and hydrogenated amorphous carbon (a-C:H) coatings on two different steel substrates, with different work hardening behavior. These brittle coatings form cracked coating segments during the in-situ tensile test. The stress transfer from the substrate to the coating segments is dependent on the elastic and elastic/plastic properties of coating and substrate. Furthermore, the segmentation of the coating together with the delamination depends strongly on the film and substrate properties. Using cohesive zone finite element modeling, the influence of substrate and coating properties on the stress transfer, segmentation of the films and on the delamination is discussed. It was found that the saturation in spacing of the cracked coating segments is either cause by a localization of the plastic strain in the substrate or by a delamination of the coating segments. Delamination only occurs, when the flow stress of the substrate is about ~ 3 times larger than the interfacial shear strength.

Journal or Publication Title: Surface and Coatings Technology
Volume: 207
Publisher: Elsevier Science Publishing Company
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Physical Metallurgy
Date Deposited: 19 Jul 2018 11:38
DOI: 10.1016/j.surfcoat.2012.06.049
Export:

Optionen (nur für Redakteure)

View Item View Item