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.

scholarly journals Indentation modulus at macro-scale level measured from Brinell and Vickers indenters by using the primary hardness standard machine at INRiM

ACTA IMEKO ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 3
Author(s):  
Alessandro Schiavi ◽  
Claudio Origlia ◽  
Alessandro Germak ◽  
Giulio Barbato ◽  
Giovanni Maizza ◽  
...  
Keyword(s):  
Contact Stiffness ◽  
Imaging Techniques ◽  
Sampling Rate ◽  
Calculation Model ◽  
Indentation Load ◽  
Indentation Modulus ◽  
Dead Weight ◽  
Microscopy Imaging ◽  
Macro Scale ◽  
Scale Range

In this paper, the experimental procedure and calculation model for the measurement of the indentation modulus by using the primary hardness standard machine at INRiM in the macro-scale range at room temperature is described. The indentation modulus is calculated based on the Doerner-Nix linear model and from accurate measurements of indentation load, displacement, contact stiffness, and hardness indentation imaging. Measurements are performed with both pyramidal (Vickers test) and spherical indenters (Brinell test). Test force is provided by a dead-weight machine, and the occurring displacement is measured by a laser-interferometric system. The geometrical dimensions of both the Vickers and Brinell indentations are measured by means of a micro-mechanical system and optical microscopy imaging techniques. Applied force and indentation depth are measured simultaneously, at a 16 Hz sampling rate, and the resultant loading-unloading indentation curve is obtained. Preliminary tests are performed on metal and alloy samples. Considerations and comments on the accuracy of the proposed method and analysis are discussed.

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.

scholarly journals Exploitation of Nanoindentation and Statistical Tools to Investigate the Behavior of Materials

2016 ◽  
Vol 6 (4) ◽  
pp. 1089-1092
Author(s):  
L. Aminallah ◽  
S. Habibi
Keyword(s):  
Polynomial Regression ◽  
Contact Stiffness ◽  
Characteristic Curve ◽  
Indentation Test ◽  
Statistical Processing ◽  
Indentation Load ◽  
Contact Depth ◽  
Characterization Of Materials

The determination of the performance of materials requires the characterization of materials at scales: macro, micro and nanoscale. Among the most common experimental methods one can find the instrumented indentation test for determining the contact stiffness and contact depth and analyzing the characteristic curve by nanoindentation load on the penetration of the indentor. Through statistical processing of the experimental results, the rigidity of contact on the contact depth is investigated, depending on the indentation load, for bronze, brass and copper. A mathematical model is adopted to describe the polynomial regression by the method of least squares growth rigidity with one or more geometric parameters representative of the size of the footprint. This study allows us to identify factors that influence the rigidity of the materials examined and the sensitivity of the used indenters.

scholarly journals Creep, Hardness, and Elastic Modulus of Lingual Fixed Retainers Adhesives

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 646 ◽  
Author(s):  
Manar Hassan ◽  
Spiros Zinelis ◽  
Monika Hersberger-Zurfluh ◽  
Theodore Eliades
Keyword(s):  
Indentation Creep ◽  
Indentation Modulus ◽  
Spearman Correlation ◽  
Orthodontic Adhesives ◽  
Spearman Correlation Test ◽  
Post Hoc ◽  
One Way Anova ◽  
Fixed Retainers

The aims of this study were twofold: a) to characterize a wide array of time-independent and -dependent properties and b) to find possible correlations among the properties tested. Seven commercially available orthodontic adhesives were included in this study and ten cylindrical specimens were prepared from each material. Five specimens from each material were used for the characterization of Martens Hardness (HM), indentation modulus (EIT), and elastic index (ηIT), and the remaining five for the determination of indentation creep (CIT). Al the aforementioned properties were identified by employing an Instrumented Indentations Testing (IIT) device with a Vickers indenter. The results of HM, EIT, ηIT, and CIT were statistically analyzed by one way ANOVA and Tukey post hoc test, while the possible correlations among the aforementioned properties were determined by Spearman correlation test. Statistical significant differences were identified for all properties among the materials tested. Spearman correlation reveals that HM has a positive correlation with EIT. Both properties demonstrated a negative correlation with ηIT and CIT, while no correlation was identified between ηIT and CIT. Significant differences in the mechanical properties tested may also imply differences in their clinical behavior and efficacy.

scholarly journals Determination of macro-scale soil properties from pore-scale structures: model derivation

2018 ◽  
Vol 474 (2209) ◽  
pp. 20170141 ◽  
Author(s):  
K. R. Daly ◽  
T. Roose
Keyword(s):  
Pore Space ◽  
Solid Particles ◽  
Underlying Structure ◽  
Pore Scale ◽  
Homogenization Procedure ◽  
Macro Scale ◽  
Model Derivation ◽  
Scale Structures ◽  
Homogenization Scheme

In this paper, we use homogenization to derive a set of macro-scale poro-elastic equations for soils composed of rigid solid particles, air-filled pore space and a poro-elastic mixed phase. We consider the derivation in the limit of large deformation and show that by solving representative problems on the micro-scale we can parametrize the macro-scale equations. To validate the homogenization procedure, we compare the predictions of the homogenized equations with those of the full equations for a range of different geometries and material properties. We show that the results differ by ≲ 2 % for all cases considered. The success of the homogenization scheme means that it can be used to determine the macro-scale poro-elastic properties of soils from the underlying structure. Hence, it will prove a valuable tool in both characterization and optimization.

scholarly journals Measurement of the Indentation Modulus and the Local Internal Friction in Amorphous SiO2 Using Atomic Force Acoustic Microscopy

2016 ◽  
Vol 61 (1) ◽  
pp. 9-12
Author(s):  
B. Zhang ◽  
H. Wagner ◽  
M. Büchsenschütz-Göbeler ◽  
Y. Luo ◽  
S. Küchemann ◽  
...  
Keyword(s):  
Internal Friction ◽  
Amorphous Materials ◽  
Contact Stiffness ◽  
Ultrasonic Transducer ◽  
Amorphous Material ◽  
Acoustic Microscopy ◽  
Damping Factor ◽  
Indentation Modulus ◽  
Amorphous Sio2 ◽  
Atomic Force

Abstract For the past two decades, atomic force acoustic microscopy (AFAM), an advanced scanning probe microscopy technique, has played a promising role in materials characterization with a good lateral resolution at micro/nano dimensions. AFAM is based on inducing out-of-plane vibrations in the specimen, which are generated by an ultrasonic transducer. The vibrations are sensed by the AFM cantilever when its tip is in contact with the material under test. From the cantilver’s contactresonance spectra, one determines the real and the imaginary part of the contact stiffness k*, and then from these two quantities the local indentation modulus M' and the local damping factor Qloc-1 can be obtained with a spatial resolution of less than 10 nm. Here, we present measured data of M' and of Qloc-1 for the insulating amorphous material, a-SiO2. The amorphous SiO2 layer was prepared on a crystalline Si wafer by means of thermal oxidation. There is a spatial distribution of the indentation modulus M' and of the internal friction Qloc-1. This is a consequence of the potential energy landscape for amorphous materials.

Quantification the Effect of the Thickness of Thin Films on their Elastic Parameters

2011 ◽  
Vol 324 ◽  
pp. 93-96 ◽  
Author(s):  
Amel Gacem ◽  
A. Doghmane ◽  
Z. Hadjoub
Keyword(s):  
Thin Films ◽  
Elasticity Modulus ◽  
Calculation Model ◽  
Thickness Variation ◽  
Acoustic Signatures ◽  
Context Modelling ◽  
Universal Relationship ◽  
Film Substrate ◽  
Material Interaction

The determination of the characteristics and properties of thin films deposited on substrates is necessary in any device application in various fields. Adequate mechanical properties are highly required for the majority of surface waves and semiconductor devices. In this context, modelling the ultrasonic-material interaction, we present results of simulation curves of acoustic signatures for multiple thin film/substrate combinations. The results obtained on several structures (Al, SiO2, ZnO, Cu, AlN, SiC and Cr)/(Al2O3, Si, Cu or Quartz) showed a velocity dispersion of the Rayleigh wave as a function of layer thickness. The development of a theoretical calculation model based on the acoustic behaviour of these structures has enabled us to quantify the dispersive evolution (positive and negative) density. Thus, we have established a universal relationship describing the density-thickness variation. In addition, networks of dispersion curves, representing the evolution of elasticity modulus (Young and shear), were determined. These charts can be used to extract the influence of thickness of layers on the variation of elastic constants

Energy Method for Determining Dynamic Characteristics of Mechanisms

1949 ◽  
Vol 16 (3) ◽  
pp. 283-288
Author(s):  
B. E. Quinn
Keyword(s):  
Dynamic Characteristics ◽  
Energy Method ◽  
Mechanical Systems ◽  
Direct Approach ◽  
Graphical Methods ◽  
Applied Forces ◽  
Complex Mechanical Systems

Abstract Two types of problems are dealt with in the paper which are involved in the design of mechanisms required to have specified dynamic characteristics: (1) Determination of applied forces required to produce specified dynamic characteristics. (2) Determination of the dynamic characteristics which will result from the application of known forces. While graphical methods may be used in the solution of type (1) problems involving more or less complex mechanical systems, they do not afford a direct approach to type (2) problems. The energy method which will be outlined can be applied in either case, although this paper will be primarily concerned with the determination of the dynamic characteristics which result when a known force is applied to a given mechanism.

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