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This content will become publicly available on January 22, 2017

Title: Delamination analysis of metal-ceramic multilayer coatings subject to nanoindentation

Internal damage has been experimentally observed in aluminum (Al)/silicon carbide (SiC) multilayer coatings subject to nanoindentation loading. Post-indentation characterization has identified that delamination at the coating/substrate interface is the most prominent form of damage. In this study the finite element method is employed to study the effect of delamination on indentation-derived hardness and Young's modulus. The model features alternating Al/SiC nanolayers above a silicon (Si) substrate, in consistence with the actual material system used in earlier experiments. Cohesive elements with a traction–separation relationship are used to facilitate delamination along the coating/substrate interface. Delamination is observed numerically to be sensitive to the critical normal and shear stresses that define the cohesive traction–separation behavior. Axial tensile stress below the edge of indentation contact is found to be the largest contributor to damage initiation and evolution. Delamination results in a decrease in both indentation-derived hardness and Young's modulus. As a result, a unique finding is that delamination can occur during the unloading process of indentation, depending on the loading condition and critical tractions.
Authors:
 [1] ;  [2]
  1. Univ. of New Mexico, Albuquerque, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Univ. of New Mexico, Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
1240095
Report Number(s):
SAND--2016-0624J
Journal ID: ISSN 0257-8972; 619060
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Surface and Coatings Technology
Additional Journal Information:
Journal Volume: 3; Journal Issue: 2; Journal ID: ISSN 0257-8972
Publisher:
Elsevier
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
nanoindentation; multilayer coating; delamination; finite element analysis