Analyzing the Influence of Test Force on Instrumented Indentation Test

2014 ◽  
Vol 685 ◽  
pp. 245-249
Author(s):  
Yang Liu ◽  
Rong Chen
Keyword(s):  
Test Data ◽  
Coefficient Of Variation ◽  
Indentation Test ◽  
Hardness Test ◽  
Relative Difference ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Instrumented Indentation ◽  
Different Levels ◽  
Instrumented Indentation Test

For the problem that the value of test force will influence the result of instrumented indentation hardness test, the relation between test force and instrumented indentation hardness , indentation modulus were investigated. 55 groups of tests were carried out, in which the test force were divided to 11 different levels. On the basis of 110 test data, differences were analyzed and the relation curves were plotted by Origin. And the relative difference value was proposed. Results show that when 19.61N≤Fmax≤98.07N, the change of test force makes little influence on instrumented indentation test (IIT) results and coefficient of variation(CV); when 0.98N≤Fmax≤9.81N or 196.14N≤Fmax≤294.21N, the change of test force makes remarkable influence on IIT results and CV.

Effect of Crystallographic Orientation on Hardness and Indentation Modulus in Austenitic Stainless Steel

2013 ◽  
Vol 586 ◽  
pp. 31-34 ◽  
Author(s):  
Petr Haušild ◽  
Aleš Materna ◽  
Jiri Nohava
Keyword(s):  
Stainless Steel ◽  
Crystallographic Orientation ◽  
Indentation Test ◽  
Indentation Load ◽  
Indentation Modulus ◽  
Instrumented Indentation ◽  
Depth Of Penetration ◽  
Indentation Method ◽  
Electron Back Scattered Diffraction ◽  
Instrumented Indentation Test

The most commonly used method for the analysis of instrumented indentation test (Oliver-Pharr) is based on isotropic elastic solution of contact problem which is not necessarily valid when indenting at the scale of one (anisotropic) grain. In this paper, we performed the grid indentation method at the sub-micron scale (at low indentation load and depth of penetration) on an area containing several grains with different crystallographic orientation which was simultaneously characterized by electron back-scattered diffraction. Measured dependencies of hardness and indentation modulus on crystallographic orientation were compared with analytical solution and finite element simulations.

Instrumented Indentation Test

2011 ◽  
pp. 167-233
Author(s):  
C. Ullner
Keyword(s):  
Indentation Test ◽  
Indentation Load ◽  
True Stress ◽  
Test Method ◽  
Indentation Hardness ◽  
Instrumented Indentation ◽  
Hardness Testing ◽  
Scope Of Application ◽  
Instrumented Indentation Test

Abstract Instrumented indentation hardness testing significantly expands on the capabilities of traditional hardness testing. It employs high-resolution instrumentation to continuously control and monitor the loads and displacements of an indenter as it is driven into and withdrawn from a material. The scope of application comprises displacements even smaller than 200 nm (nano range) and forces even up to 30 kN . Mechanical properties are derived from the indentation load-displacement data obtained in simple tests. The chapter presents the elements of contact mechanics that are important for the application of the instrumented indentation test. The test method according to the international standard (ISO 14577) is discussed, and this information is supplemented by information about the testing technique and some example applications. The chapter concludes with a discussion on the extensions of the standard that are expected in the future (estimation of the measurement uncertainty and procedures for the determination of true stress-strain curves).

Elastic recovery and reloading of hardness impressions with a conical indenter

2002 ◽  
Vol 750 ◽  
Author(s):  
A. C. Fischer-Cripps
Keyword(s):  
Residual Stress ◽  
Test Data ◽  
Elastic Recovery ◽  
Indentation Test ◽  
Nanoindentation Test ◽  
Instrumented Indentation ◽  
Specimen Material ◽  
Elastic Event ◽  
Instrumented Indentation Test ◽  
Elastic Unloading

ABSTRACTThe present work is concerned with the analysis of elastic unloading data in conventional methods of analysis of nanoindentation test data. Experimental and finite element results are used to show that the reloading of a residual impression with and without the presence of residual stress is an elastic event, and further shows that the estimation of modulus and hardness computed using established techniques is in error due to the assumption the sides of the residual impression are straight. This work calls into question the validity of commonly used methods of test and analysis of instrumented indentation test data that use the elastic unloading data as the basis for the calculation of modulus and hardness of the specimen material.

scholarly journals Conventional Vickers and true instrumented indentation hardness determined by instrumented indentation tests

2010 ◽  
Vol 25 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Seung-Kyun Kang ◽  
Ju-Young Kim ◽  
Chan-Pyoung Park ◽  
Hyun-Uk Kim ◽  
Dongil Kwon
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Material Properties ◽  
Indentation Test ◽  
Indentation Hardness ◽  
Instrumented Indentation ◽  
Real Contact ◽  
Wide Range ◽  
Indentation Tests ◽  
Instrumented Indentation Test

We evaluate Vickers hardness and true instrumented indentation test (IIT) hardness of 24 metals over a wide range of mechanical properties using just IIT parameters by taking into account the real contact morphology beneath the Vickers indenter. Correlating the conventional Vickers hardness, indentation contact morphology, and IIT parameters for the 24 metals reveals relationships between contact depths and apparent material properties. We report the conventional Vickers and true IIT hardnesses measured only from IIT contact depths; these agree well with directly measured hardnesses within ±6% for Vickers hardness and ±10% for true IIT hardness.

Evaluation of Tensile Properties Profile of Weld Zone Using Instrumented Indentation

2010 ◽  
Author(s):  
Seung-Kyun Kang ◽  
Young-Cheon Kim ◽  
Chan-Pyoung Park ◽  
Dongil Kwon
Keyword(s):  
Tensile Properties ◽  
Weld Zone ◽  
Indentation Test ◽  
Tensile Tests ◽  
Structural Safety ◽  
Small Scale ◽  
Stress And Strain ◽  
Instrumented Indentation ◽  
Deformation And Fracture ◽  
Instrumented Indentation Test

Understanding the property distribution in the weld zone is very important for structural safety, since deformation and fracture begin at the weakest point. However, conventional tensile tests can measure only average material properties because they require large specimens. Small-scale tests are being extensively researched to remove this limitation, among such tests, instrumented indentation test (IIT) are of great interest because of their simple procedures. Here we describe the evaluation of tensile properties using IIT and a representative stress-strain approach. The representative stressstrain method, introduced in 2008 in ISO/TR29381, directly correlates the stress and strain under the indenter to the true stress and strain of tensile testing by defining representative functions. Using this technique, we successfully estimate the yield strength and tensile strength of structural metallic materials and also obtain profiles of the weld-zone tensile properties.

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