Determination of creep parameters of materials by indentation load relaxation approach

2016 ◽  
pp. 41-46 ◽  
Keyword(s):  
Indentation Load ◽  
Load Relaxation

Determination of Time-Dependent Plastic Properties of Metals by Indentation Load Relaxation Techniques

1984 ◽  
Vol 40 ◽  
Author(s):  
Simo-Pekka Hannula ◽  
Donald Stone ◽  
Che-Yu Li
Keyword(s):  
Thin Film ◽  
Indentation Test ◽  
Indentation Load ◽  
Time Dependent ◽  
Relaxation Techniques ◽  
Load Relaxation ◽  
Surface Layers ◽  
Plastic Properties ◽  
Load Relaxation Test

AbstractLoad relaxation testing has been demonstrated to be useful for characterizing the time dependent plastic properties of metals. However, for testing of small material volumes, such as thin film metallizations, thin films, and contact surfaces, conventional load relaxation techniques cannot be used. For such applications an indentation test offers an attractive means for obtaining data necessary for materials characterization. This work shows that an indentation load relaxation test is experimentally feasible for thin film testing. Experiments on brass and beryllium copper samples with or without a gold/nickel plating illustrate different relaxation properties of the substrates and the surface layers. Furthermore, results of experiments on some fcc metals suggest rather simple relations between the conventional uniaxial load relaxation (LR) test and the indentation load relaxation (ILR) test.

Indentation load relaxation experiments with indentation depth in the submicron range

1990 ◽  
Vol 5 (10) ◽  
pp. 2100-2106 ◽  
Author(s):  
W. R. LaFontaine ◽  
B. Yost ◽  
R. D. Black ◽  
C-Y. Li
Keyword(s):  
Indentation Depth ◽  
Metal Films ◽  
Indentation Load ◽  
Hard Substrate ◽  
Flow Properties ◽  
Load Relaxation ◽  
Relaxation Data ◽  
Flow Curves ◽  
Relaxation Experiments

Indentation load relaxation (ILR) experiments with indentation depths in the submicron range are described. Under appropriate conditions, the ILR data are found to yield flow curves of the same shape as those based on conventional load relaxation data. Variations in flow properties as a function of depth in submicron metal films deposited on a hard substrate are detected by the experiments described.

Spherical indentation load-relaxation of soft biological tissues

2006 ◽  
Vol 21 (8) ◽  
pp. 2003-2010 ◽  
Author(s):  
Jason M. Mattice ◽  
Anthony G. Lau ◽  
Michelle L. Oyen ◽  
Richard W. Kent
Keyword(s):  
Costal Cartilage ◽  
Kidney Tissue ◽  
Biological Tissues ◽  
Indentation Load ◽  
Spherical Indentation ◽  
Load Relaxation ◽  
Soft Biological Tissues ◽  
Long Time ◽  
Constant Displacement ◽  
Soft Biological Materials

Elastic-viscoelastic correspondence was used to generate displacement–time solutions for spherical indentation testing of soft biological materials with time-dependent mechanical behavior. Boltzmann hereditary integral operators were used to determine solutions for indentation load-relaxation following a constant displacement rate ramp. A “ramp correction factor” approach was used for routine analysis of experimental load-relaxation data. Experimental load-relaxation tests were performed on rubber, as well as kidney tissue and costal cartilage, two hydrated soft biological tissues with vastly different mechanical responses. The experimental data were fit to the spherical indentation ramp-relaxation solutions to obtain values of short- and long-time shear modulus and of material time constants. The method is used to demonstrate linearly viscoelastic responses in rubber, level-independent indentation results for costal cartilage, and age-independent indentation results for kidney parenchymal tissue.

scholarly journals Evaluation of capabilities of the nanoindentation test in the determination of flow stress characteristics of the matrix material in porous sinters

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lukasz Madej ◽  
Adam Legwand ◽  
Mohan Setty ◽  
Mateusz Mojzeszko ◽  
Konrad Perzyński ◽  
...  
Keyword(s):  
Flow Stress ◽  
Scale Effects ◽  
Imaging Techniques ◽  
Matrix Material ◽  
Indentation Load ◽  
Nanoindentation Test ◽  
Load Range ◽  
Nanoindentation Measurement ◽  
The Matrix

AbstractHerein, we evaluate the nanoindentation test capabilities in the determination of flow stress characteristics of the matrix material in porous sinters. The Distaloy AB sample with 15% porosity after the sintering operation is selected as a case study for the investigation. 2D and 3D imaging techniques are employed first to highlight difficulties in identifying reliable nano hardness measurement zones for further properties evaluation. Then, nanoindentation test results are acquired with Berkovich tip pressed under various loads at different locations in the sample. Systematic indentations in the quartz sample are used as a cleaning procedure to minimize the effect of the possible build-up around the indenter tip. The representative indentation load range is selected based on the extracted material characteristics. With that, the stress–strain response of the sinter matrix material is identified. The reliability of the determined flow stress curve is confirmed with the use of conical nanoindentation measurement results and finite element simulations. Obtained results show that it is possible to calculate reliable flow stress characteristics of the matrix in the porous samples, with the assumption that experiments under various loading conditions and from various locations in the matrix are performed. It is also pointed out that various indentation loads should be used to eliminate the influence of the pile-up or scale effects that affect the overall material response.

Indentation Load Relaxation Studies of Thin Film-Substrate Systems

1986 ◽  
Vol 72 ◽  
Author(s):  
D. Stone ◽  
W. Lafontaine ◽  
S. Ruoff ◽  
S.-P. Hannula ◽  
B. Yost ◽  
...  
Keyword(s):  
Thin Film ◽  
Aluminum Film ◽  
Indentation Load ◽  
Load Relaxation ◽  
Tin Film ◽  
Relaxation Studies ◽  
Film Substrate

AbstractResults from indentation load relaxation (ILR) tests on thin film-substrate systems are reported. In the case of a 1 pum aluminum film on silicon, the data can be interpreted as reflecting both the properties of the film and the interface between film and substrate. Data from a 37μm TiN film on 304 SS are believed to reflect the combined behavior of the film and substrate.

Determination of Mechanics Properties of a Piezoelectric Material Using Indentation Method with a Cylindrical Indenter

2011 ◽  
Vol 335-336 ◽  
pp. 1014-1020 ◽  
Author(s):  
Bin Zhao
Keyword(s):  
Piezoelectric Materials ◽  
Contact Stiffness ◽  
Transversely Isotropic ◽  
Indentation Load ◽  
The Finite Element Method ◽  
Poling Direction ◽  
Piezoelectric Effects ◽  
Piezoelectric Strain ◽  
Piezoelectric Solids

The Finite Element Method (FEM) was used for axisymmetric indentation to investigate mechanics properties of piezoelectric solids (PZT-5H). Since piezoelectric materials are usually treated as transversely isotropic elastic materials, a simple linear relationship between indentation load P and indentation displacement h was presented under a cylindrical indenter. Three different cases (uncouple mechanical case, poled substrate-insulating indenter and poled substrate-conducting indenter) were taken into consideration to study indentation responses. The results showed that polarization could more easily damage the poled substrate than the uncoupled case. At the same displacement the highest indentation load existed in the poled/insulating case and the lowest one was in the uncoupled case because of the polarization influence. Electric potential distributions were given to study the direct piezoelectric effects and the electromechanical phenomena. In addition elastic modulus, contact stiffness, and piezoelectric strain constant were calculated directly through the use of the FEM. The determination of the poling direction is another use for the indentation technique, and the discussion of indentation size effect shows that a bigger indenter is followed by a larger indentation load.

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).

Determination of Precise Indentation Flow Properties of Metallic Materials Through Analyzing Contact Characteristics Beneath Indenter

2005 ◽  
Vol 127 (3) ◽  
pp. 265-272 ◽  
Author(s):  
Sung-Hoon Kim ◽  
Min-Kyung Baik ◽  
Dongil Kwon
Keyword(s):  
Fe Simulation ◽  
Indentation Load ◽  
Metallic Materials ◽  
Flow Properties ◽  
Element Analysis ◽  
Property Data ◽  
Testing Data ◽  
Tension Testing ◽  
Continuous Indentation

The continuous indentation technique is widely used for nondestructive evaluation of the mechanical properties of devices and materials. In particular, flow properties can be obtained by using this technique with a spherical indenter. Several formulas have been suggested to determine flow properties, and they commonly require the determination of the precise contact characteristics such as the contact area or depth between material and indenter to obtain the properties accurately. In this study, contact characteristics were determined by analysis of the contact morphology from FEA (finite element analysis) using mechanical property data for several steels. The contact characteristics obtained from FE simulation were compared to an analysis of the parameters of indentation load-depth curves for the steels. The contact characteristics were shown as functions of such parameters as work-hardening exponent and indentation depth. In addition, using indentation morphology from FE simulation, the flow properties were evaluated by analysis of indentation morphology for 18 materials on the basis of the two representative preexisting definitions of stress and strain, and the definitions were verified by comparison of the flow properties with tension testing data.

Effects of Surface Stress on the Load-Depth Curves of Depth-Sensing Indentation

2004 ◽  
Vol 841 ◽  
Author(s):  
Q. Wang ◽  
K. Ozaki
Keyword(s):  
Surface Stress ◽  
Fem Simulation ◽  
Indentation Load ◽  
Depth Sensing ◽  
Residual Surface Stress ◽  
Experimental Scheme ◽  
Elastic Unloading ◽  
Depth Curves ◽  
Good Agreement

ABSTRACTBased on the effects of residual surface stress on the unloading curves of indentation load-depth responses, an experimental scheme for determination of the residual stress by depth-sensing indentation is proposed. From the point that the elastic unloading portion of the load-depth curves can be expected to be unaffected by the residual stresses, the formula for evaluating surface stress by indentation is derived based on energy method. The proposed formula is verified by using FEM simulated indentation load-depth responses for different surface stress levels. The levels of surface stress evaluated by the proposed formula show a good agreement with the ones used as input parameters in FEM simulation.

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