Indentation Fracture Toughness of Sintered Silicon Carbide in the Palmqvist Crack Regime

Li, Zhuang; Ghosh, Ashish; Kobayashi, A. S.; Bradt, R. C.

doi:10.1111/j.1151-2916.1989.tb06242.x

Cited by 194 publications

(88 citation statements)

References 22 publications

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“…Thus fracture toughness measurement using Vickers indentation is only accurate if is already determined, which is not the case for many BMGs where sample size prohibits bending tests. The accuracy of indentation results calculated using a standard "calibration" constant (0.016) have been shown to deviate about 50% from standard ASTM K IC measurements of SiC samples [30,32].…”

Section: Journal Of Metallurgymentioning

confidence: 99%

Bulk Mechanical Properties Testing of Metallic Marginal Glass Formers

Phan

Kelly

Kassner

et al. 2016

Journal of Metallurgy

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We developed a unique three-point bend testing apparatus to measure bulk mechanical properties of a model metallic glass alloy (SAM2X5 with nominal composition Fe 49.7 Cr 17.1 Mn 1.9 Mo 7.4 W 1.6 B 15.2 C 3.8 Si 2.4 ) prepared by spark plasma sintering. The relatively large sample sizes in the present work allowed for the preparation of test specimens with a macroscale cross section (in the millimeter range) with well-controlled sample dimensions closer to standardized tests. Wire saw cutting allowed for a relatively sharp notch radius (3x smaller than previous studies) and minimal sample damage. We determined that Young's modulus and notch fracture toughness measured by our three-point bending apparatus are 230 GPa and 4.9 MPa⋅m 1/2 . Also, Vickers indentation and flexure testing provided consistent results for Young's modulus. Indentation fracture toughness measured by Vickers indentation produced values at least 50% lower than by flexure. The microscale mechanical properties testing technique presented in this work and subsequent analyses are applicable to specimens of other compositions or ones prepared by other methods.

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Section: Journal Of Metallurgymentioning

confidence: 99%

Bulk Mechanical Properties Testing of Metallic Marginal Glass Formers

Phan

Kelly

Kassner

et al. 2016

Journal of Metallurgy

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“…Median half-penny-shaped cracks occur when high indentation loads are applied [19,32,40]. The profile of a median half-penny-shaped crack is illustrated in Fig.…”

Section: Propagation Of the Crack Geometry During The Vickers Indentamentioning

confidence: 99%

“…Different ceramics have various equations applicable to calculate their K 1c . Preparation of the samples involves polishing in order to create a reflective surface plane (this would mean that the surface has been well polished) [9,10,32,33] prior to the Vickers indentation process. There are still constraints with the Vickers indentation techniques, as reported by Gong [34], compared with the more conventional techniques applied, such as the SENB and double-torsion (DT) methods, as mentioned elsewhere [17,[35][36][37].…”

Section: Vickers Indentation Techniquementioning

confidence: 99%

Fracture Toughness of a Zirconia Engineering Ceramic and the Effects Thereon of Surface Processing with Fibre Laser Radiation

Shukla

Lawrence

2010

Proceedings of the Institution of Mechanical Engineers, Part B:

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Vickers hardness indentation tests were employed to investigate the near-surface changes in the hardness of a fibre laser-treated and an as-received ZrO 2 engineering ceramic. Indents were created using 5, 20, and 30 kg loads to obtain the hardness. Optical microscopy, white-light interferometry, and a coordinate measuring machine were then used to observe the crack lengths and crack geometry. Palmqvist and half-penny median crack profiles were found, which dictated the selection of the group of equations used herein. Computational and analytical approaches were then adapted to determine the K 1c of ZrO 2 . It was found that the best applicable equation was:1/2 (P/c 3/2 ), which was confirmed to be 42 per cent accurate in producing K 1c values within the range of 8 to 12 MPa m 1/2 for ZrO 2 . Fibre laser surface treatment reduced the surface hardness and produced smaller crack lengths in comparison with the as-received surface. The surface crack lengths, hardness, and indentation loads were found to be important, particularly the crack length, which significantly influenced the end K 1c value when K 1c ¼ 0.016 (E/H) 1/2 (P/c 3/2 ) was used. This is because, the longer the crack lengths, the lower the ceramic's resistance to indentation. This, in turn, increased the end K 1c value. Also, the hardness influences the K 1c , and a softer surface was produced by the fibre laser treatment; this resulted in higher resistance to crack propagation and enhanced the ceramic's K 1c . Increasing the indentation load also varied the end K 1c value, as higher indentation loads resulted in a bigger diamond footprint, and the ceramic exhibited longer crack lengths.

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“…The comparison of Vickers and Knoop' hardness for ceramics material reported by several authors [27,28] showed that the average value of the ratio H K /H V is 1.105.…”

Section: Mechanical Characterizationmentioning

confidence: 99%

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

Nsar¹,

Hassine²,

Bouzouita³

2013

JBNB

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Biological apatites contain several elements as traces. In this work, magnesium and fluorine co-substituted hydroxyapatites with the general formula Ca 9 Mg(PO 4 ) 6 (OH) 2-y F y , where y = 0, 0.5, 1, 1.5 and 2 were synthesized by the hydrothermal method. After calcination at 500˚C, the samples were pressureless sintered between 950˚C and 1250˚C. The substitution of F − for OH − had a strong influence on the densification behavior and mechanical properties of the materials. Below 1200˚C, the density steeply decreased for y = 0.5 sample. XRD analysis revealed that compared to hydroxylfluorapatite containing no magnesium, the substituted hydroxyfluorapatites decomposed, and the nature of the decomposition products is tightly dependent on the fluorine content. The hardness, elastic modulus and fracture toughness of these materials were investigated by Vickers's hardness testing. The highest values were 622 ± 4 GPa, 181 ± 1 GPa and 1.85 ± 0.06 MPa·m 1/2 , respectively.

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Indentation Fracture Toughness of Sintered Silicon Carbide in the Palmqvist Crack Regime

Cited by 194 publications

References 22 publications

Bulk Mechanical Properties Testing of Metallic Marginal Glass Formers

Bulk Mechanical Properties Testing of Metallic Marginal Glass Formers

Fracture Toughness of a Zirconia Engineering Ceramic and the Effects Thereon of Surface Processing with Fibre Laser Radiation

Sintering and Mechanical Properties of Magnesium and Fluorine Co-Substituted Hydroxyapatites

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