Effect of Microstructure on Mechanical Properties and Cutting Performance of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-Ti(C, N) Ceramics

Koyama, Takashi; Uchida, Susumu; Nishiyama, A.

doi:10.2109/jcersj.100.520

Cited by 14 publications

(9 citation statements)

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“…Al 2 O 3 + (Ti,W)C composite material has shown a maximal density value of 99.7% TD15, significantly higher than the material with niobium carbide (98.5% TD). But the hardness value now obtained (19.5 GPa) is comparable to those reported for alumina + Ti(C,N) (20 GPa) 6 , alumina + WC (19 GPa) 15 and alumina + NbC (19.7 GPa) 4 . Contrary to what was observed regarding hardness, the fracture toughness shows a pronounced improvement in the Alumina + (Ti,W)C system by an addition of niobium carbide.…”

Section: Methodssupporting

confidence: 86%

“…Figure 3 shows the effect of (Ti,W)C + NbC presence on hardness and fracture toughness of alumina composites. Results found on both properties performed on similar hot-pressed Al 2 O 3 reinforced composite material, which are also presented for comparison purposes [2][3][4][5][6][7][8]10,15 . The hardness obtained in this work was lower than that for alumina + (Ti,W)C, alumina + TiC, alumina + WC + Co, alumina + MgB 2 and alumina + TiB 2 + SiCwhisker.…”

Section: Methodsmentioning

confidence: 99%

“…This effect can probably be attributed to the lower density of the material when compared to other composite materials. The hardness values could be improved by adding hard particles and decreased as the microstructure becomes coarser and more porous 4,6,7 . Al 2 O 3 + (Ti,W)C composite material has shown a maximal density value of 99.7% TD15, significantly higher than the material with niobium carbide (98.5% TD).…”

Section: Methodsmentioning

confidence: 99%

“…However, hot-pressed alumina-based ceramic composite reinforced with refractory carbides and others elements have been developed as technological alternatives to cemented carbides [2][3][4][5] . Studies published in the literature relevant to alumina ceramics reinforced with (Ti(C,N), WC, TiB 2 /SiCwhisker, TiC and MgB 2 particles have shown increase of the wear resistance, hardness, fracture toughness and thermal shock resistance 3,[6][7][8][9][10] . The aluminabased composite materials present good mechanical properties, in order to replace WC-Co in some special applications, such as machine cast iron and other metals and alloys.…”

Section: Introductionmentioning

confidence: 99%

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The influence of (Ti,W)C and NbC on the mechanical behavior of alumina

Acchar

Cairo

2006

Mat. Res.

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Recent studies published in the literature have focused on reinforcing alumina with different refractory carbides and nitrides in order to improve hardness, fracture toughness and wear resistance. The incorporation of hard particles as WC, (Ti,W)C and NbC on alumina matrix has shown to be a good alternative in improving the mechanical properties of the composite material. The present work reports some preliminary results obtained reinforcing alumina with 20 wt. (%) (Ti,W)C and 10 wt. (%) NbC. Alumina, (Ti,W)C and NbC powders were homogenized and mixed in a planetary ball mill and subsequently hot-pressed at 1650 °C under 20 MPa in flowing argon. Specimens were characterized by Vicker`s microhardness (H V ), fracture toughness (K IC ), X ray diffraction and scanning microscopy. The composite material showed hardness values of 19.5 GPa and fracture toughness values ≈ 5.2 MPa.m 1/2 . The high fracture toughness encountered in this work is related to the crack deflection mechanism.

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Section: Methodssupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of (Ti,W)C and NbC on the mechanical behavior of alumina

Acchar

Cairo

2006

Mat. Res.

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“…Hardness has been improved by the dispersion of hard particles, such as WC [1], TiC [2,[5][6], TiN [7][8], Cr 3 C 2 and NbC [10,11]. Niobium carbide displays a good potential for reinforcing alumina, due to its high hardness (>20 GPa) and high melting temperature (3600 o C).…”

Section: Introductionmentioning

confidence: 99%

Study of the Surface Composition on Alumina-NbC Composites

Silva

Acchar

Costa

et al. 2001

phys. stat. sol. (a)

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The aim of this work is to analyse an alumina-NbC based composite ceramic made from a polymeric precursor (polysiloxane), alumina and metallic niobium. The materials have a fixed concentration of 60 wt% of polymer and 40% of a mixture of niobium and alumina. These materials are mixed and sintered at 1450 C for 6 h. Alumina based composites have been proposed as excellent materials for use as cutting tools, so knowledge of the superficial composition is extremely important because it is directly related to the hardness and abrasion resistance. Analysis of the surface composition was carried out by electron spectroscopy. It should be emphasized that there may be a meaningful difference between the surface and the interior composition due to a eventual processes such as element segregation to the surface and/or diffusion of elements from the surface to the sample bulk. The analysis was performed by XPS and Auger for three niobium concentrations 10, 20 and 40 wt%, and the results show the appearance of niobium on the surface only at the Nb composition of 10 wt%; this appears to be due to a process of niobium atom migration to the interior of the sample or one involving niobium bonds. For the 10 wt% sample after sintering, the formation of NbC on the surface and the presence of niobium Auger peaks were observed. However, for concentrations larger than 10 wt%, oxides and sub-oxides (NbO, NbO 2 , etc.) were formed which may result in the absence of niobium peaks in the spectra. The analysis of the ratio of niobium to carbon atoms at the surface shows a value of 0.1 which reveals that the quantity of niobium and carbon is not sufficient for ideal formation of niobium carbide (NbC). Under these conditions it is verified that there is only a slight formation of niobium carbide on the surface, which is harmful to the hardness of the material. The excess niobium tends to diffuse towards the interior of the sample and react with the oxygen forming sub-oxides.

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Friction and wear of ZrO₂‐TiO₂ surface‐alloyed Al₂O₃ ceramics in unlubricated sliding contact

Gahr

Lee

1994

Materialwissenschaft Werkst

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Slightly and highly porous , 4 1 2 0 3 ceramics were surface remelted and alloyed by adding ZrO? and Ti02 using infrared C 0 2 laser radiation. The rcsulting compositc laycrs of thickness of about 200 pm containcd about 31 voI.% o f Z r 0 2 -and Ti02-rich phases which wcrc homogcncously distributcd at the grain boundaries of the alumina matrix. Microstructurcs and worn surfaces werc analysed by electron microscopy and EDX analysis. Tribological tcsts werc carried o u t unlubricatcd using conditions of abrasivc wear and oscillating sliding wcar. rcspcctivcly.The rcsults showcd t h a t the avcragc grain sizc and hardness of the ceramics wcrc rcduccd due t o alloying. Dcspite decreasing hardness the wciir rcsistiince was substantially increased. Friction and wear of thc untrentcd ceramics depended strongly on the amount of porosity which was rcmovcd or substantially reduced by laser trcatnicnt. Surface alloying of AI2O3 ccramics can offer an effective process for producing components showing very different surface and bulk propcrtics and particularly improved tribological behaviour. For the alloying elements and cxpcrimcntal conditions used, the improvement was more pronounced in wear resistance than in friction cocfficicnt. Reibung und VerschleiB von Zr02-Ti02 oberflachenlegierter A1203-Keramik im ungeschmierten GleitkontaktA1203-Keramikcn mit unterschiedlichcr Porositat wurden mit Hilfe von C02-Laserstrahlung umgeschmolzen und durch Zusatze von Z r 0 2 und Ti02 oberflachenlegicrt. Die legierten Oberflachenschichten wiesen Dicken von etwa 200 pm und etwa 31 vol.% an Zr02und Ti02-reichen Phascn auf. Die zweiten Phasen waren homogcn in der Oberfliichc vcrteilt und bildcten sich bevorzugt an den Korngrcnzcn dcr cc-Al2Oi-Matrix. Elektronenmikroskopische und EDX-Analysen wurdcn an den Lxgierungsschichten und den verschlissenen Obcrflachcn vorgenommcn.TribologischeVersuche wurden ungeschmiert unter Bedingungen des Furchungsver-schleiRes gegcn Sic-Abrasivstoff und dcs Schwingungsversch-IeiBes gegen A1203 in Labortribometern durchgefuhrt.Die Ergebnisse zeigten, dalJ die mittlere KorngrolJe und die HBrte in den lcgierten Oberflachen geringer, die Zahigkeit jedoch gr6Rer war. Die Ausgangsporositat der Kcramiken beeinflul3te deutlich dic tribologischcn Eigcnschaften. Durch die Laserbehandlung wurdc dic Porosit2t beseitigt oder bei der hochporosen A1203-Kcramik his auf einc gcringc Restporositat reduziert. Die Untersuchungcn zeigten, dal3 Obcrflachcnlcgieren von AI20?-Kcrarnik eine effektive Tcchnologie darstellt, um Bauteile mit unterschicdlichen Oberflachen-und Volumeneigenschaften sowie im vorliegenden Fall mit stark verbcssertcn tribologischen Eigenschaften herzustellen. Hierbei konntc unter den gewahlten Bedingungcn besonders der Verschlciljwidcrstand erhiiht werden.

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Effect of Microstructure on Mechanical Properties and Cutting Performance of Al<sub>2</sub>O<sub>3</sub>-Ti(C, N) Ceramics

Cited by 14 publications

References 0 publications

The influence of (Ti,W)C and NbC on the mechanical behavior of alumina

The influence of (Ti,W)C and NbC on the mechanical behavior of alumina

Study of the Surface Composition on Alumina-NbC Composites

Friction and wear of ZrO₂‐TiO₂ surface‐alloyed Al₂O₃ ceramics in unlubricated sliding contact

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Effect of Microstructure on Mechanical Properties and Cutting Performance of Al<sub>2</sub>O<sub>3</sub>-Ti(C, N) Ceramics

Cited by 14 publications

References 0 publications

The influence of (Ti,W)C and NbC on the mechanical behavior of alumina

The influence of (Ti,W)C and NbC on the mechanical behavior of alumina

Study of the Surface Composition on Alumina-NbC Composites

Friction and wear of ZrO2‐TiO2 surface‐alloyed Al2O3 ceramics in unlubricated sliding contact

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Friction and wear of ZrO₂‐TiO₂ surface‐alloyed Al₂O₃ ceramics in unlubricated sliding contact