Measurement of Elastic Modulus and Yield Stress by AFM Ultra-Micro-Hardness Tester.

Nano-scale hardness and elastic modulus of WC-Co composites and their relationship to the tool life during particleboards milling. The paper summarizes the results of the technique of hardness and elastic modulus determination using a load and displacement sensing indentation experiments. During the tests these properties were measured in nano-scale for different types of WC-Co composites using the Anton Paar TriTec Ultra Nano Hardness Tester (UNHT). In addition, durability examination of WC-Co tools during milling of particleboard was carried out. In the final stage, the correlation of the studied properties with the lifetime of tools was analyzed. The studies have revealed a relationship between micro-hardness and the total cutting length of the WC-Co tools.

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Evaluation of Load Parameters and Hold Time of a Vickers Ultra-Micro Hardness Tester for Measure of Hardness and Modulus of Elasticity of Dental Composites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.912.130 ◽

2018 ◽

Vol 912 ◽

pp. 130-135 ◽

Cited By ~ 2

Author(s):

Tereza Cristina Favieri Melo-Silva ◽

Cláudio Luis Melo-Silva ◽

Cristiane Fonseca Carvalho ◽

A.B. Teixeira ◽

E.C. Carvalho ◽

...

Keyword(s):

Elastic Modulus ◽

Modulus Of Elasticity ◽

Hybrid Composites ◽

Hold Time ◽

Dental Composites ◽

Micro Hardness ◽

Inorganic Particles ◽

Hardness Tester ◽

Vickers Indenter ◽

Hardness Values

The aim of this study was to standardize the parameters for testing the hardness and elastic modulus for dental composites. It used the equipment Dynamic Ultra Micro Hardness Tester DUH-211 / DUH-211S (Shimadzu) varying the load and the hold time. two composites were used with various inorganic particles that were embedded and sanded for the assay. one Vickers indenter was used being held nine rows with ten penetrations. For each composite loads were used (20, 50 and 100gf) and times (zero, five and ten seconds). The results showed that the effect of the load and the hold time had influence on the modulus and hardness values of the studied composites. The authors concluded that loads and hold larger team showed greater stability of hardness values and modulus of elasticity for the studied composites and these values for both hybrid composites as for nanoparticulate were dependent on load and time.

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Shear modulus and yield stress of foams: contribution of interfacial elasticity

Soft Matter ◽

10.1039/d0sm02246b ◽

2021 ◽

Vol 17 (14) ◽

pp. 3937-3944

Author(s):

Annika R. Völp ◽

Norbert Willenbacher

Keyword(s):

Elastic Modulus ◽

Block Copolymer ◽

Shear Modulus ◽

Yield Stress ◽

Protein Food ◽

General Correlation

A general correlation of foam shear modulus G0 and yield stress τy with the interfacial elastic modulus of foaming solutions in shear and dilation E∞ was found for surfactant, block-copolymer, protein, food, and particle-stabilized foams.

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Microstructure and Grain Abrasion Properties of Cr3C2-NiCr Coating Prepared by Laser Cladding Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.271-272.3 ◽

2012 ◽

Vol 271-272 ◽

pp. 3-7

Author(s):

Long Wei ◽

Zong De Liu ◽

Xin Zhi Li ◽

Ming Ming Yuan ◽

Cheng Yuan Zhong

Keyword(s):

Wear Resistance ◽

Wear Rate ◽

Laser Cladding ◽

Micro Hardness ◽

High Quality ◽

Wear Resistant ◽

Hardness Tester ◽

Technology Analysis ◽

Main Component

Cr3C2-NiCr has high quality of wear resistant properties and is widely used in abrasive environment. In this paper, Cr3C2-NiCr coating was prepared on 45 steel by laser cladding technology. Analysis and research of the coatings were achieved by SEM and XRD to determine the main component and the different region on coatings. The hardness and the element component were investigated by micro-hardness tester and EDS. Abrasion tests were performed to contrast the wear resistance of two materials. The results indicate that the hardness of the coatings is nearly 3 times as the substrate. The coatings are well combined with the substrate and the phase of Cr3C2 has a large proportion in the coatings. Abrasion tests show that the average of wear rate on substrate is 5.2 times as the coatings.

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Evolutions of Microstructure for Multilayered Al-Mg Alloy Composites by Accumulation Roll Bonding (ARB) Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.411.527 ◽

2011 ◽

Vol 411 ◽

pp. 527-531

Author(s):

Bing Zhang ◽

Zhong Wei Chen ◽

Shou Qian Yuan ◽

Tian Li Zhao

Keyword(s):

Multilayer Structure ◽

Optical Microscope ◽

Alloy Layer ◽

Mg Alloy ◽

Micro Hardness ◽

Roll Bonding ◽

Fine Grained ◽

Hardness Tester ◽

Average Grain Size ◽

Evolution Of Microstructure

In this paper, accumulative roll bonding (ARB) has been used to prepare the Al/Mg alloy multilayer structure composite materials with 1060Al sheet and MB2 sheet. The evolution of microstructure of the cladding materials during ARB processes was observed by optical microscope, scanning electron microscopy, and micro-hardness was measured by micro-hardness tester. The results show that a multilayer structure material of Al/Mg alloy with excellent bonding characteristics and fine grained microstructure was prepared by ARB processes. With the ARB cycles increasing, Mg alloy layer in multilayer composite material was necked and fractured, and the hardness of the Al and Mg alloy was increased. Average grain size was less than 1μm after ARB4 cycles.

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Influence of the resistive-pulse welding parameters of nickel super-alloys on selected properties of the connection

Mechanik ◽

10.17814/mechanik.2017.11.180 ◽

2017 ◽

Vol 90 (11) ◽

pp. 1060-1062

Author(s):

Sławomir Spadło ◽

Wojciech Depczyński ◽

Piotr Młynarczyk ◽

Tadeusz Gajewski ◽

Jarosław Dąbrowa

Keyword(s):

Optical Microscope ◽

Mechanical Tests ◽

Welding Parameters ◽

Thin Sheets ◽

Micro Hardness ◽

Hastelloy X ◽

Haynes 230 ◽

Hardness Tester ◽

Resistive Pulse ◽

Pulse Welding

Microstructure and mechanical tests of welds of thin sheets made from nickel-based super-alloys (Haynes 230 and Hastelloy X) were presented. The welds were made using the resistive-pulse micro-welding method using the WS 7000S device. The micro-hardness of the joints was measured with a Matsuzawa Vickers MX 100 hardness tester at 100 G (0.98 N). Metallographic observations of the prepared micro-sections were performed using the Nikon Eclipse MA200 optical microscope at various magnifications. The metallographic microstructure studies were supplemented by linear analysis of the chemical composition, for which the OXFORD X-MAX electron microscope was applied.

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Effect of growth conditions on the mechanical properties of lanthanum-gallium tantalate crystals

Modern Electronic Materials ◽

10.3897/j.moem.6.2.63731 ◽

2020 ◽

Vol 6 (2) ◽

pp. 65-70

Author(s):

Mark V. Weintraub ◽

Nina S. Kozlova ◽

Evgeniya V. Zabelina ◽

Mikhail I. Petrzhik

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Elastic Recovery ◽

Growth Conditions ◽

Piezoelectric Response ◽

Instrumented Indentation ◽

Recovery Coefficient ◽

Hardness Tester ◽

Growth Atmosphere ◽

Oxygen Addition

The effect of growth conditions, anisotropy and polarity of specimens on the mechanical properties of lanthanum-gallium tantalate La3Ta0.5Ga5.5O14 single crystals grown in different atmospheres (argon (Ar), argon with oxygen addition (Ar+(<2%)O2 and Ar+(2%)O2) and air) was studied. The test specimens for the measurements were cut perpendicularly to a 3rd order axis (Z cuts) and in polar directions perpendicular to a 2nd order axis (Y cuts). The polarity of the Y cut specimens was tested by piezoelectric response. The brittleness was evaluated by microindentation at 3, 5, 10 and 25 g loads. The brittleness proved to show itself at a 5 g and the higher loads regardless of growth atmosphere. Therefore microhardness tests were done at loads of within 3 g. The microhardness HV of the specimens was measured with an DM 8B Affri microhardness tester by Vickers methods. The hardness H, elastic modulus E and elastic recovery coefficient R were measured with a Berkovich pyramid on a CSM Nano-Hardness Tester using the instrumented indentation (nanoindentation) method. Growth atmosphere was shown to affect the mechanical properties of lanthanum-gallium tantalate crystals: crystals grown in an oxygen-free argon atmosphere had the lowest microhardness, hardness, elastic modulus and elastic recovery coefficient. The lowest microhardness was detected in Z cut specimens regardless of growth atmosphere. The mechanical properties of polar Y cuts proved to be anisotropic: the microhardness, hardness, elastic modulus and elastic recovery coefficient of these cuts were lower for positive cuts than for negative ones regardless of growth atmosphere. Y and Z cut langatate specimens grown in argon with less than two percent oxygen exhibited strong elastic modulus and elastic recovery coefficient anisotropy.

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Biomimetic composites inspired by venous leaf

Journal of Composite Materials ◽

10.1177/0021998317707254 ◽

2017 ◽

Vol 52 (3) ◽

pp. 361-372 ◽

Cited By ~ 2

Author(s):

Gongdai Liu ◽

R Ghosh ◽

A Vaziri ◽

A Hossieni ◽

D Mousanezhad ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Yield Stress ◽

Poisson’S Ratio ◽

Composite Structures ◽

Volume Fraction ◽

Matrix Material ◽

Poisson's Ratio ◽

Fiber Volume ◽

Young’S Moduli

A typical plant leaf can be idealized as a composite having three principal fibers: the central mid-fiber corresponding to the mid-rib, straight parallel secondary fibers attached to the mid-fiber representing the secondary veins, and then another set of parallel fibers emanating from the secondary fibers mimicking the tertiary fibers embedded in a matrix material. This paper introduces a biomimetic composite design inspired by the morphology of venous leafs and investigates the effects of venation morphologies on the in-plane mechanical properties of the biomimetic composites using finite element method. The mechanical properties such as Young’s moduli, Poisson’s ratio, and yield stress under uniaxial loading of the resultant composite structures was studied and the effect of different fiber architectures on these properties was investigated. To this end, two broad types of architectures were used both having similar central main fiber but differing in either having only secondary fibers or additional tertiary fibers. The fiber and matrix volume fractions were kept constant and a comparative parametric study was carried out by varying the inclination of the secondary fibers. The results show that the elastic modulus of composite in the direction of main fiber increases linearly with increasing the angle of the secondary fibers. Furthermore, the elastic modulus is enhanced if the secondary fibers are closed, which mimics composites with closed cellular fibers. In contrast, the elastic modulus of composites normal to the main fiber ( x direction) exponentially decreases with the increase of the angle of the secondary fibers and it is little affected by having secondary fibers closed. Similar results were obtained for the yield stress of the composites. The results also indicate that Poisson’s ratio linearly increases with the secondary fiber angle. The results also show that for a constant fiber volume fraction, addition of various tertiary fibers may not significantly enhance the mechanical properties of the composites. The mechanical properties of the composites are mainly dominated by the secondary fibers. Finally, a simple model was proposed to predict these behaviors.

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Machine learning-based design strategy for 3D printable bioink: elastic modulus and yield stress determine printability

Biofabrication ◽

10.1088/1758-5090/ab8707 ◽

2020 ◽

Vol 12 (3) ◽

pp. 035018 ◽

Cited By ~ 6

Author(s):

Jooyoung Lee ◽

Seung Ja Oh ◽

Sang Hyun An ◽

Wan-Doo Kim ◽

Sang-Heon Kim

Keyword(s):

Machine Learning ◽

Elastic Modulus ◽

Yield Stress ◽

Design Strategy

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In Vitro Re-Hardening of Bleached Enamel Using Mineralizing Pastes: Toward Preventing Bacterial Colonization

Materials ◽

10.3390/ma13040818 ◽

2020 ◽

Vol 13 (4) ◽

pp. 818 ◽

Cited By ~ 5

Author(s):

Andrea Scribante ◽

Claudio Poggio ◽

Simone Gallo ◽

Paolo Riva ◽

Antonella Cuocci ◽

...

Keyword(s):

Bacterial Colonization ◽

Micro Hardness ◽

Home Agent ◽

Vickers Hardness Number ◽

Hardness Tester ◽

Post Hoc ◽

To Receive ◽

Hardness Values ◽

At Home

The search for materials able to remineralize human hard tissues is a modern medical challenge. In this study, the protective effect on the enamel microhardness by a paste based on hydroxyapatite and sodium fluoride (Remin Pro) was evaluated after two different enamel bleaching procedures. Forty sound human incisors were randomly assigned to different treatments: bleaching with an in-office agent (Perfect Bleach Office+); bleaching with an at-home agent (Perfect Bleach); bleaching with the in-office agent followed by the prophylaxis paste; bleaching with the at-home agent followed by the prophylaxis paste; no treatment (control). Bleaching was performed at 0, 8, 24 and 32 h, followed by a 3-min re-mineralizing treatment in the subgroups designed to receive it. Specimens underwent a micro-hardness tester and a mean Vickers Hardness number was considered for each specimen. ANOVA exhibited significant differences among groups. Post-hoc Tukey testing showed significant micro-hardness decrease after the application of both the two bleaching agents. The treatment with prophylaxis paste significantly increased the micro-hardness values of bleached enamel.

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