scholarly journals An alternative to the determination of the effective zero point in instrumented indentation: Use of the slope of the indentation curve at indentation load values

2012 ◽  
Vol 40 ◽  
pp. 356-363 ◽  
Author(s):  
P. Brammer ◽  
O. Bartier ◽  
X. Hernot ◽  
G. Mauvoisin ◽  
S.-S. Sablin
Keyword(s):  
Zero Point ◽  
Indentation Load ◽  
Instrumented Indentation ◽  
Indentation Curve

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instrumentation to continuously control and monitor the loads and displacements of an indenter as it is driven into and withdrawn from a material.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).

scholarly journals Indentation Modulus, Indentation Work and Creep of Metals and Alloys at the Macro-Scale Level: Experimental Insights into the Use of a Primary Vickers Hardness Standard Machine

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2912
Author(s):  
Alessandro Schiavi ◽  
Claudio Origlia ◽  
Alessandro Germak ◽  
Andrea Prato ◽  
Gianfranco Genta
Keyword(s):  
Contact Stiffness ◽  
Calculation Model ◽  
Indentation Load ◽  
Indentation Creep ◽  
Indentation Modulus ◽  
Indentation Curve ◽  
Metrological Research ◽  
Macro Scale ◽  
Applied Forces

In this work, the experimental method and the calculation model for the determination of indentation moduli, indentation work, and indentation creep of metallic materials, by means of macroscale-level forces provided by a primary hardness standard machine at the National Institute of Metrological Research (INRIM) at the at room temperature were described. Indentation moduli were accurately determined from measurements of indentation load, displacement, contact stiffness and hardness indentation imaging and from the slope of the indentation unloading curve by applying the Doerner-Nix linear model; indentation work, representing the mechanical work spent during the force application of the indentation procedure, was determined by calculating the areas under the loading–unloading indentation curve, through fitting experimental data with a polynomial law. Measurements were performed with a pyramidal indenter (Vickers test). The applied force was provided by a deadweight machine, and the related displacement was measured by a laser interferometric system. Applied forces and the occurring indentation depths were simultaneously measured: the resulting loading–unloading indentation curve was achieved. Illustrative tests were performed on metals and alloy samples. Discussion and comments on the suitability of the proposed method and analysis were reported.

Regularities and properties of instrumented indentation diagrams obtained by ball-shaped indenter

2020 ◽  
Vol 86 (5) ◽  
pp. 43-51
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
P. V. Volkov ◽  
D. A. Zhgut
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Elastoplastic Deformation ◽  
Elastic Limit ◽  
Tensile Tests ◽  
Indentation Load ◽  
International Standards ◽  
Instrumented Indentation ◽  
Indentation Methods ◽  
Special Points

The history of appearance and the current state of instrumented indentation are briefly described. It is noted that the materials instrumented indentation methods using a pyramid and ball indenters are actively developing and are currently regulated by several Russian and international standards. These standards provide formulas for calculating the Young’s modulus and hardness at maximum indentation load. Instrumented indentation diagrams «load F – displacement α» of a ball indenter for metallic materials were investigated. The special points on the instrumented indentation diagrams «F – α» loading curves in the area of elastic into elastoplastic deformation transition, and in the area of stable elastoplastic deformation are revealed. A loading curve area with the load above which the dF/dα begins to decrease is analyzed. A technique is proposed for converting «F – α» diagrams to «unrestored Brinell hardness HBt – relative unrestored indent depth t/R» diagrams. The elastic and elastoplastic areas of «HBt – t/R» diagrams are described by equations obtained analytically and experimentally. The materials strain hardening parameters during ball indentation in the area of elastoplastic and plastic deformation are proposed. The similarity of «HBt – t/R» indentation diagram with the «stress σ – strain δ» tensile diagrams containing common zones and points is shown. Methods have been developed for determining hardness at the elastic limit, hardness at the yield strength, and hardness at the ultimate strength by instrumented indentation with the equations for their calculation. Experiments on structural materials with different mechanical properties were carried out by instrumented indentation. The values of hardness at the elastic limit, hardness at the yield strength and hardness at the ultimate strength are determined. It is concluded that the correlations between the elastic limit and hardness at the elastic limit, yield strength and hardness at the yield strength, ultimate tensile strength and hardness at the ultimate strength is more justified, since the listed mechanical characteristics are determined by the common special points of indentation diagrams and tensile tests diagrams.

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.

Evaluation of Young’s modulus of construction materials by instrumented indentation using a ball indenter

2021 ◽  
Vol 87 (8) ◽  
pp. 64-68
Author(s):  
V. M. Matyunin ◽  
A. Yu. Marchenkov ◽  
N. Abusaif ◽  
M. V. Goryachkina ◽  
R. V. Rodyakina ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
High Surface ◽  
Construction Materials ◽  
Contact Problems ◽  
Indentation Load ◽  
Test Material ◽  
Elastic Displacement ◽  
Large Radius ◽  
Instrumented Indentation

Methods for evaluation of Young’s modulus (Em) of structural materials by instrumented indentation using ball indenter have been considered. All these techniques are based on the solution of elastic contact problems performed by H. Hertz. It has been shown that registration of the initial elastic region in the «load – displacement» indentation diagram provides the Em determination for metals and alloys. However, it is necessary to evaluate accurately the elastic compliance of a device, to use an indenter with a large radius R, and ensure a high surface quality of the test material in advance. Methods for Em determation, when indentation diagrams are recorded in the elastoplastic indentation region, should include the effect of plastic deformation on the elastic displacement calculated by H. Hertz expression. However, it appeared essential to determine the relation between the elastic αel and plastic h components of the total elastoplastic displacement α and the elastic displacement α0 estimated by H. Hertz expression for a definite indentation load. A close correlation between α0 and αel is revealed for steels, aluminum, magnesium, and titanium alloys when using indenters with a radius of R = 0.2 – 5 mm (diameter D = 0.4 – 10 mm) and maximum indentation load Fmax = 47 – 29430 N (4.8 – 3000 kgf). It is also shown that a gradual decrease in Em is observed with an increase in R(D) at the same degree of loading F/D2 for the same material. This fact was explained by the scale factor effect.

scholarly journals Effect of the New Equinox Definition on the Zero-Point of Longitude of the Indian Calendar

1990 ◽  
Vol 141 ◽  
pp. 186-186
Author(s):  
A. K. Bhatnagar
Keyword(s):  
Initial Point ◽  
Zero Point ◽  
The Mean ◽  
Image Position ◽  
Calendar Reform

Indian calendars follow a sidereal system of astronomy taking a fixed initial point on the ecliptic as the origin from which the longitudes are measured. Its position for the official Indian Calendar has been defined by the Calendar Reform Committee (1955) as the point on the ecliptic whose true tropical longitude was 23°15′00″ as on 21 March 1956, 0h UT. Its position was determined upto the year 1984 in accordance with Newcomb's value for general precession using the relation where T is in centuries of 36525 ephemeris days from 1900 January 0.5 ET. Recent changes in the location and the motion of the equinox with reference to the epoch J2000.0 have necessitated corresponding changes to be included in the determination of the mean and true positions of the above initial point. The new algorithm worked out is where T is in Julian centuries of 36525 days from J2000.0.

Instrumented indentation microscope applied to the elastoplastic indentation contact mechanics of coating/substrate composites

2009 ◽  
Vol 24 (6) ◽  
pp. 1950-1959 ◽  
Author(s):  
N. Hakiri ◽  
A. Matsuda ◽  
M. Sakai
Keyword(s):  
Contact Area ◽  
Film Coating ◽  
Instrumented Indentation ◽  
Thin Film Coating ◽  
Composite Systems ◽  
Indentation Tests ◽  
Film Substrate ◽  
Contact Parameters

In instrumented indentation tests for a thin film coating on a substrate (film/substrate composite), it is well known that the substrate-affected contact area estimated through conventional approximations includes significant uncertainties, leading to a crucial difficulty in determining the elastic modulus and the contact hardness. To overcome this difficulty, an instrumented indentation microscope that enables researchers to make an in situ determination of the contact area is applied to an elastoplastic film on substrates having various values of their elastic moduli. Using the indentation microscope, the substrate-affected indentation contact parameters including contact hardness of the film/substrate composites are determined directly as well as quantitatively without any undesirable assumptions and approximations associated with the contact area estimate. The effect of a stiffer substrate on the contact profile of impression is significant, switching the profile from sinking in to piling up during penetration, and resulting in the substrate-affected contact hardness being highly enhanced at deeper penetrations. Through the present experimental study, it is demonstrated how efficient that instrumented indentation microscopy is in determining the substrate-affected elastoplastic contact parameters of film/substrate composite systems.

Analysis on Mechanical Properties of Instrumented Indentation Tester Frame

2012 ◽  
Vol 215-216 ◽  
pp. 895-898
Author(s):  
Jun Hong Guo ◽  
De Jun Ma ◽  
Wei Chen ◽  
Zhong Kang Song
Keyword(s):  
High Precision ◽  
Inclination Angle ◽  
Indentation Load ◽  
Measurement Precision ◽  
Instrumented Indentation ◽  
Element Analysis ◽  
Maximum Value ◽  
Load Analysis ◽  
The Relationship ◽  
Maximum Inclination

Finite element analysis is undertaken to identify the extent of loading deformation of instrumented indentation equipment frame which is a main part in High-precision instrumented indentation tester developed and realized by our group. The working load enacted in the model is varied from 10N to 100N, and the increment load is 10N. By plotting and fitting data of inclination angle and working load, the relationship between frame inclination angle and working load is established. The function of this relationship is θ=0.000024*F. When the working load is up to the upper bound 100N, the inclination angle of frame reaches the maximum value 0.00241°.Load analysis of push rod shows that the percent error between measured load values and real indentation load values caused by maximum inclination angle is in 10-8order. The conclusion is thus derived that frame inclination has nearly no effects on load measurement precision. The research in this paper confirms that the design of frame belonging to High-precision instrumented indentation tester is appropriate.

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