Nanohardness of Individual Phases in WC – Co Cemented Carbides

The nanohardness of WC – Co hardmetals has been investigated using instrumented indentation and Berkovich tip indenter. The nanohardness, HIT, and indentation modulus, EIT, of Co phase and individual WC grains and the influence of their crystalographic orientation have been studied. SEM, AFM and EBSD methods were used for the characterization of the microstructures and indents and for the identification of crystallographic orientation of WC grains, respectively. Strong indentation load-size effect and significant influence of the crystallographic orientation of WC crystals on HIT and EIT have been found. The nanohardness of Co binder was approximately 10 GPa and that of WC grains varied between 25 and 50 GPa, depending on the grain orientation and load. The nanohardness values of the basal and prismatic planes of individual WC grains at load of 10 mN were 40.4 ± 1.6 GPa and 32.8 ± 2.0 GPa, respectively.

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Effect of Crystallographic Orientation on Hardness and Indentation Modulus in Austenitic Stainless Steel

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.586.31 ◽

2013 ◽

Vol 586 ◽

pp. 31-34 ◽

Cited By ~ 3

Author(s):

Petr Haušild ◽

Aleš Materna ◽

Jiri Nohava

Keyword(s):

Stainless Steel ◽

Crystallographic Orientation ◽

Indentation Test ◽

Indentation Load ◽

Indentation Modulus ◽

Instrumented Indentation ◽

Depth Of Penetration ◽

Indentation Method ◽

Electron Back Scattered Diffraction ◽

Instrumented Indentation Test

The most commonly used method for the analysis of instrumented indentation test (Oliver-Pharr) is based on isotropic elastic solution of contact problem which is not necessarily valid when indenting at the scale of one (anisotropic) grain. In this paper, we performed the grid indentation method at the sub-micron scale (at low indentation load and depth of penetration) on an area containing several grains with different crystallographic orientation which was simultaneously characterized by electron back-scattered diffraction. Measured dependencies of hardness and indentation modulus on crystallographic orientation were compared with analytical solution and finite element simulations.

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Indentation Load-Size Effect in Al2O3 — SIC Nanocomposites

Journal of Electrical Engineering ◽

10.2478/v10187-011-0047-y ◽

2010 ◽

Vol 61 (5) ◽

pp. 305-307 ◽

Cited By ~ 6

Author(s):

Erika CsehovAaA ◽

Jana AndrejovskAaA ◽

Apichart Limpichaipanit ◽

Ján Dusza ◽

Richard Todd

Keyword(s):

Size Effect ◽

Vickers Hardness ◽

Indentation Load ◽

Proportional Specimen Resistance ◽

Load Size ◽

Hardness Values ◽

True Hardness

Indentation Load-Size Effect in Al2O3 — SIC Nanocomposites The indentation load-size effect (ISE) in Vickers hardness of Al2O3 and Al2O3 + SiC nanocomposites has been investigated and analysed using Meyer law, proportional specimen resistance (PSR) model and modified proportional specimen resistance (MPSR) model. The strongest ISE was found for alumina. Both the PSR and MPSR models described the ISE well, but the MPSR model resulted in slightly lower true hardness values for all materials investigated. No evidence of the effect of machining stresses on the ISE has been found.

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Small-Scale Mechanical Testing of Cemented Carbides from the Micro- to the Nano-Level: A Review

Metals ◽

10.3390/met9050502 ◽

2019 ◽

Vol 9 (5) ◽

pp. 502 ◽

Cited By ~ 8

Author(s):

Naughton-Duszová ◽

Csanádi ◽

Sedlák ◽

Hvizdoš ◽

Dusza

Keyword(s):

Mechanical Testing ◽

Cobalt Content ◽

Cemented Carbides ◽

Future Research ◽

Small Scale ◽

Indentation Modulus ◽

Compression Tests ◽

Clear Trend ◽

Testing Environment ◽

Load Size

In this overview, we summarize the results published to date concerning the small-scale mechanical testing of WC–Co cemented carbides and similar hardmetals, describing the clear trend in the research towards ever-smaller scales (currently at the nano-level). The load-size effect during micro/nanohardness testing of hardmetals and their constituents and the influence of the WC grain orientation on their deformation, hardness, indentation modulus, fracture toughness, and fatigue characteristics are discussed. The effect of the WC grain size/orientation, cobalt content, and testing environment on damage accumulation, wear mechanisms, and wear parameters are summarized. The deformation and fracture characteristics and mechanical properties, such as the yield and compression strength, of WC–Co composites and their individual WC grains at different orientations during micropillar compression tests are described. The mechanical and fracture properties of micro-cantilevers milled from WC–Co hardmetals, single WC grains, and cantilevers containing WC/WC boundaries with differently-oriented WC grains are discussed. The physical background of the deformation and damage mechanisms in cemented carbides at the micro/nano-levels is descri and potential directions for future research in this field are outlined.

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Indentation Testing of an Al2O3/Al2O3 + ZrO2 Layered Composite

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.290.316 ◽

2005 ◽

Vol 290 ◽

pp. 316-319

Author(s):

Peter Zimovčák ◽

Tibor Köves ◽

Ján Dusza ◽

Ladislav Pešek ◽

Francis Chalvet ◽

...

Keyword(s):

Fracture Toughness ◽

Residual Stresses ◽

Size Effect ◽

Vickers Hardness ◽

Layered Composite ◽

Indentation Load ◽

Indentation Fracture ◽

Depth Sensing ◽

The Individual ◽

Load Size

Micro- and macro-hardness of the individual layers of an Al2O3 / Al2O3 + ZrO2 layered composite have been investigated. The indentation load size effect has been studied in a range of indentation load of 25 mN – 100 N using depth sensing indentation technique and conventional Vickers hardness testers. Fracture toughness values of the layers have been measured using indentation fracture method. The effect of residual stresses on the KIC value has been analyzed.

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Mechanical properties from instrumented indentation: Uncertainties due to tip-shape correction

Journal of Materials Research ◽

10.1557/jmr.1998.0401 ◽

1998 ◽

Vol 13 (10) ◽

pp. 2936-2944 ◽

Cited By ~ 23

Author(s):

L. E. Seitzman

Keyword(s):

Mechanical Properties ◽

Indentation Load ◽

Indentation Modulus ◽

Statistical Uncertainty ◽

Constant Modulus ◽

Vickers Indentation ◽

Instrumented Indentation ◽

Shape Correction ◽

Load Displacement

The quality of hardness H and indentation modulus E* measurements from instrumented indentation is investigated. Load-displacement data from glass and sapphire are obtained by Vickers indentation and converted to H and E* through a series of equations, including those for tip-shape correction. The quality of H and E* is determined by calculating the statistical uncertainty at each step and propagating the uncertainty to the next step. Conventional tip-shape corrections, assuming either constant hardness or constant modulus, introduce significant errors in H and E* when single, continuous correction functions are used. Piecewise correction functions are shown to improve the quality of H and E*. This investigation demonstrates the importance of calculating and propagating uncertainty at each step when converting instrumented indentation load-displacement data to mechanical properties.

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Hardness and indentation load-size effect in Al2O3-SiC nanocomposite

Metallic Materials ◽

10.4149/km_2011_2_119 ◽

2011 ◽

Vol 49 (2) ◽

pp. 119-124 ◽

Cited By ~ 2

Author(s):

E. CSEHOVA ◽

J. ANDREJOVSKA ◽

A. LIMPICHAIPANIT ◽

J. DUSZA ◽

R. TODD

Keyword(s):

Size Effect ◽

Indentation Load ◽

Load Size

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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 ◽

10.3390/ma13184155 ◽

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.

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