Extended characterization of materials based on continuous instrumented indentation diagrams

2021 ◽  
Vol 2021 (3) ◽  
pp. 10-23
Author(s):  
B. A. Galanov ◽  
◽  
S. M. Ivanov ◽  
V. V. Kartuzov ◽  
◽  
...  
Keyword(s):  
Material Flow ◽  
Elastic Moduli ◽  
Contact Stiffness ◽  
Relative Size ◽  
Indentation Hardness ◽  
Instrumented Indentation ◽  
Characterization Of Materials ◽  
Instrumental Indentation

In addition to the traditional determination of hardness and elastic moduli from continuous diagrams of instrumental indentation, it is proposed to determine the yield stress, the characteristic of plasticity, the characteristic relative size of the elastoplastic zone under the indenter, and the volumetric deformation of the material in the area of contact of the indenter with the sample. The indentation diagram shows the transition point to the unconstrained material flow under the indenter. Keywords: indentation, hardness, elastic moduli, contact stiffness, elastic-plastic strains.

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.

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).

Characterization of Superplastic Materials by Results of Free Bulging Tests

2016 ◽  
Vol 838-839 ◽  
pp. 552-556 ◽  
Author(s):  
Sergey A. Aksenov ◽  
Ivan Y. Zakhariev ◽  
Aleksey V. Kolesnikov ◽  
Sergey A. Osipov
Keyword(s):  
Simple Technique ◽  
Main Idea ◽  
Main Subject ◽  
Material Constants ◽  
Element Simulation ◽  
Simplified Solution ◽  
Characterization Of Materials ◽  
Free Bulging

Determination of material constants describing its behavior during superplastic gas forming is the main subject of this study. The main feature of free bulging tests is the stress-strain conditions which are very similar to ones occurring in the most of gas forming processes. On the other hand, the interpretation of the results of such tests is a complicated procedure. The paper presents a simple technique for the characterization of materials superplasticity by free bulging tests, which is based on inverse analysis. The main idea of this technique is a semianalytical solution of the direct problem instead of finite element simulation which allows one to reduce the calculation time significantly. At the same time the results this simplified solution are accurate enough to obtain realistic material constants.

scholarly journals Micromechanical Characterization of Complex Polypropylene Morphologies by HarmoniX AFM

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
S. Liparoti ◽  
A. Sorrentino ◽  
V. Speranza
Keyword(s):  
Elastic Moduli ◽  
Force Microscopy ◽  
Atomic Force ◽  
Indentation Tests ◽  
Injection Molded ◽  
Micromechanical Characterization ◽  
Complex Polymer ◽  
Good Agreement

This paper examines the capability of the HarmoniX Atomic Force Microscopy (AFM) technique to draw accurate and reliable micromechanical characterization of complex polymer morphologies generally found in conventional thermoplastic polymers. To that purpose, injection molded polypropylene samples, containing representative morphologies, have been characterized by HarmoniX AFM. Mapping and distributions of mechanical properties of the samples surface are determined and analyzed. Effects of sample preparation and test conditions are also analyzed. Finally, the AFM determination of surface elastic moduli has been compared with that obtained by indentation tests, finding good agreement among the results.

scholarly journals Characterization of Residual Stresses and Accumulated Plastic Strain Induced by Shot Peening through Simulation of Instrumented Indentation

2014 ◽  
Vol 996 ◽  
pp. 367-372 ◽  
Author(s):  
Yu Gang Li ◽  
Pascale Kanoute ◽  
Manuel François
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Residual Stresses ◽  
Shot Peening ◽  
Fe Simulation ◽  
Contact Stiffness ◽  
Maximum Load ◽  
Instrumented Indentation ◽  
Contour Plots

In this study, a method based on finite element (FE) simulation was proposed for characterizing simultaneously residual stresses (RS) and accumulated plastic strain (PP) induced by shot peening process. Through a series of simulations of instrumented indentation, contour plots of several parameters, as maximum load, contact hardness and contact stiffness, were computed. By superposing them pair-wisely, RS and PP mixed together could be characterized simultaneously. In order to verify the method, several simulations with different combinations of RS and PP were performed. Results showed that the method is promising but remains to be tested on experimental acquisitions.

Comparative Experimental Analysis of Different Bending Methods for the Mechanical Characterization of Materials with Previous Loading History (Stress-Strain Curves)

2011 ◽  
Vol 314-316 ◽  
pp. 1377-1382
Author(s):  
David Torres Franco ◽  
Guillermo Urriolagoitia-Sosa ◽  
Guillermo Urriolagoitia-Calderón ◽  
Luis Hector Hernandez Gomez ◽  
Beatriz Romero Angeles ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Compression Stress ◽  
Loading History ◽  
Stress Strain ◽  
Axial Tensile ◽  
Tension And Compression ◽  
Characterization Of Materials ◽  
Previous Loading

Until now, the most common way to obtain the stress-strain curves for a material is through axial tensile testing. However, in recent years there have been developments on alternative methods for material characterization. In this sense, the bending procedure has proved to be a powerful technique, which allows simultaneous determination of tension and compression stress behavior by the use of bending moment and strain data. The characterization of materials by means of bending data was presented for the first time in 1910 by the German engineer Herbert. Some years later Nadai and Marin developed some research on this procedure. More recently, several researchers (Mayville and Finnie, Laws and Urriolagoitia-Sosa, et.al.) have developed diverse bending methods for the simultaneous determination of tension and compression stress-strain curves. In this paper, three bending methods are analyzed and compared against axial tensile and compressive results. It was decided to apply each one of the bending procedures to bent rectangular cross sections beams made from 6063-T5 Aluminum alloy. The specimens were annealed to eliminate previous loading history and axially pulled to induce a controlled anisotropic behavior (strain hardening and Bauschinger effect). The results obtained by two of the three methods provided great confidence and have certified the application of this new technique to characterize material.

scholarly journals The Influence of the Third Element on Nano-Mechanical Properties of Iron Borides FeB and Fe2B Formed in Fe-B-X (X = C, Cr, Mn, V, W, Mn + V) Alloys

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4155
Author(s):  
Ivana Kirkovska ◽  
Viera Homolová ◽  
Ivan Petryshynets ◽  
Tamás Csanádi
Keyword(s):  
Mechanical Properties ◽  
Indentation Size Effect ◽  
Microstructural Characterization ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Instrumented Indentation ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
X Ray

In this study, the influence of alloying elements on the mechanical properties of iron borides FeB and Fe2B formed in Fe-B-X (X = C, Cr, Mn, V, W, Mn + V) alloys were evaluated using instrumented indentation measurement. The microstructural characterization of the alloys was performed by means of X-ray diffraction and scanning electron microscope equipped with an energy dispersive X-ray analyzer. The fraction of the phases present in the alloys was determined either by the lever rule or by image analysis. The hardest and stiffest FeB formed in Fe-B-X (X = C, Cr, Mn) alloys was observed in the Fe-B-Cr alloys, where indentation hardness of HIT = 26.9 ± 1.4 GPa and indentation modulus of EIT = 486 ± 22 GPa were determined. The highest hardness of Fe2B was determined in the presence of tungsten as an alloying element, HIT = 20.8 ± 0.9 GPa. The lowest indentation hardness is measured in manganese alloyed FeB and Fe2B. In both FeB and Fe2B, an indentation size effect was observed, showing a decrease of hardness with increasing indentation depth.

scholarly journals Spectroelectrochemical Determination of Isoprenaline in a Pharmaceutical Sample

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5179
Author(s):  
Fabiola Olmo ◽  
Jesus Garoz-Ruiz ◽  
Julia Carazo ◽  
Alvaro Colina ◽  
Aranzazu Heras
Keyword(s):  
Optical Fibers ◽  
Reaction Mechanisms ◽  
Sodium Metabisulfite ◽  
Dual Sensor ◽  
Drug Sample ◽  
Pharmaceutical Sample ◽  
Parallel Configuration ◽  
Characterization Of Materials

UV/Vis absorption spectroelectrochemistry (SEC) is a multi-response technique that has been commonly used for the characterization of materials and the study of reaction mechanisms. However, it has been scarcely used for quantitative purposes. SEC allows us to obtain two analytical signals simultaneously, yielding a dual sensor in just one experiment. In the last years, our group has developed new devices useful for analysis. In this work, a SEC device in parallel configuration, based on optical fibers fixed on screen-printed electrodes, was used to determine isoprenaline in a commercial drug, using both, the electrochemical and the spectroscopic signals. In this commercial drug, isoprenaline is accompanied in solution by other compounds. Among them is sodium metabisulfite, an antioxidant that strongly interferes in the isoprenaline determination. A simple pretreatment of the drug sample by bubbling wet-air allows us to avoid the interference of metabisulfite. Here, we demonstrate again the capabilities of UV/Vis absorption SEC as double sensor for analysis and we propose a simple pretreatment to remove interfering compounds.

scholarly journals Macro-, Micro- and Nanomechanical Characterization of Crosslinked Polymers with Very Broad Range of Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2951
Author(s):  
Miroslav Slouf ◽  
Beata Strachota ◽  
Adam Strachota ◽  
Veronika Gajdosova ◽  
Vendulka Bertschova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Moduli ◽  
Polymer Networks ◽  
Polymeric Materials ◽  
Indentation Creep ◽  
Indentation Hardness ◽  
Hardness Testing ◽  
Length Scales ◽  
Nanomechanical Properties

This work is focused on the comparison of macro-, micro- and nanomechanical properties of a series of eleven highly homogeneous and chemically very similar polymer networks, consisting of diglycidyl ether of bisphenol A cured with diamine terminated polypropylene oxide. The main objective was to correlate the mechanical properties at multiple length scales, while using very well-defined polymeric materials. By means of synthesis parameters, the glass transition temperature (Tg) of the polymer networks was deliberately varied in a broad range and, as a result, the samples changed their mechanical behavior from very hard and stiff (elastic moduli 4 GPa), through semi-hard and ductile, to very soft and elastic (elastic moduli 0.006 GPa). The mechanical properties were characterized in macroscale (dynamic mechanical analysis; DMA), microscale (quasi-static microindentation hardness testing; MHI) and nanoscale (quasi-static and dynamic nanoindentation hardness testing; NHI). The stiffness-related properties (i.e., storage moduli, indentation moduli and indentation hardness at all length scales) showed strong and statistically significant mutual correlations (all Pearson′s correlation coefficients r > 0.9 and corresponding p-values < 0.001). Moreover, the relations among the stiffness-related properties were approximately linear, in agreement with the theoretical prediction. The viscosity-related properties (i.e., loss moduli, damping factors, indentation creep and elastic work of indentation at all length scales) reflected the stiff-ductile-elastic transitions. The fact that the macro-, micro- and nanomechanical properties exhibited the same trends and similar values indicated that not only dynamic, but also quasi-static indentation can be employed as an alternative to well-established DMA characterization of polymer networks.

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