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Materials characterization part I: contact area of the Berkovich indenter for nanoindentation tests

Jamal, M and Morgan, MN (2017) Materials characterization part I: contact area of the Berkovich indenter for nanoindentation tests. International Journal of Advanced Manufacturing Technology. ISSN 0268-3768

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Abstract

This is the first of two papers associated with materials characterization methods based on hardness testing. This paper presents a method to determine the area function of the Berkovich indenter used in nanoindentation hardness tests. The geometry and hence projected area of the indenter is known to affect the force-displacement response of a material during the loading and unloading stages. It is therefore important that the projected area is accurately defined to ensure determination of correct material hardness values. It is shown that values for the projected area determined from numerical methods applied to experimental data differ from values predicted inversely from theory based on the assumption of perfect tip geometry. This difference is attributed principally to a blunting of the tip, presenting as a tip radius. A simulation of the nanoindentation hardness test system is developed using finite element modelling (FEM) methods. Solutions for a range of load indentation curves obtained from experiment with fused silica are determined from best fit analyses using the root mean square error objective function (RMSE). A linear regression method is subsequently developed and used to estimate the area function. A parametric study of simulation and experimental results has been completed to verify the FEM and to assess the influence of varying tip curvature on force-displacement response during the loading and unloading stages and is summarily reported. A new method of analysis for determination of area function is proposed for use with numerical-based simulations, which for the first time, accommodates variation in tip geometry and which is shown to deliver improved agreement with nanoindentation experimental results. The second paper will focus on the study of the tip geometry of the Vickers microindenter. © 2017 Springer-Verlag London

Item Type: Article
Additional Information: The final publication is available at Springer via http://dx.doi.org/10.1007/s00170-017-0115-6
Uncontrolled Keywords: 09 Engineering, 08 Information And Computing Sciences, 01 Mathematical Sciences
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TJ Mechanical engineering and machinery
Divisions: General Engineering Research Institute
Publisher: Springer
Date Deposited: 28 Mar 2017 11:07
Last Modified: 13 Sep 2017 10:40
DOI or Identification number: 10.1007/s00170-017-0115-6
URI: http://researchonline.ljmu.ac.uk/id/eprint/6134

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