scholarly journals Fabrication of WC-Graphene-Al Composites by Rapid Sintering and Their Mechanical Properties

2021 ◽  
Vol 59 (6) ◽  
pp. 384-391
Author(s):  
In-Jin Shon
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Cutting Tools ◽  
High Hardness ◽  
Tungsten Carbides ◽  
Al Content ◽  
Hardness Tester ◽  
Al Composite ◽  
Rapid Sintering ◽  
Composite Form

Tungsten carbides are very attractive because of their superior properties, e.g., high thermal and electrical conductivities, high melting point, high hardness, and relatively high chemical stability. Tungsten carbides with a binder metal, for example Ni or Co, are mainly used to fabricate nozzles, molds and cutting tools in the composite form. Al has been reported as an alternative binder in Tungsten carbide since Al shows a higher oxidation resistance than Ni or Co and is less expensive. Nanostructured WC-Graphene-Al composites were sintered rapidly using pulsed current activated sintering (PCAS). The mechanical properties (hardness and fracture toughness) and microstructure were investigated using scanning electron microscopy and Vickers hardness tester. The PCAS method successfully obstructed grain growth, resulting in nanostructured materials, and induced a very fast consolidation nearly at the level of theoretical density. The grain size of WC in WC-Graphene-Al composite decreased with the addition of Al content. The fracture toughness and hardness of the WC-5vol.% graphene-x vol.% Al (x=0, 5, 10, 15) were 4.7, 5.5, 5.9, 7.9 MPa·m1/2 and 2008, 1961, 1883, 1731 kg/mm2, respectively. The fracture toughness was improved without remarkable decrease of hardness due to the small dimensions of the WC grain and the consolidation facilitated by adding Al to WC-Graphene matrix.

scholarly journals Mechanical Properties and Rapid Sintering of WC-BN-Al Composites

2020 ◽  
Vol 58 (7) ◽  
pp. 453-458
Author(s):  
Seong-Eun Kim ◽  
Su-Hwan Hong ◽  
In-Jin Shon
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Cutting Tools ◽  
High Hardness ◽  
Tungsten Carbides ◽  
Hardness Tester ◽  
Electrical Conductivities ◽  
Rapid Sintering ◽  
Composite Form ◽  
Binder Metal

Tungsten carbides are quite attractive for their superior properties, e.g., high melting point, high hardness, high thermal and electrical conductivities, and relatively high chemical stability. Tungsten carbides with a binder metal, for example Co or Ni, are mainly used to produce cutting tools, nozzles and molds in the composite form. But these binder materials show inferior chemical characteristics compared to the tungsten carbide phase. There has been enormous interest recently in finding alternative binder phases because of the low corrosion resistance and the high cost of Ni or Co. Al has been reported as an alternative binder for WC and TiC, since Al is less expensive and shows a higher oxidation resistance than Ni or Co. Nanostructured WC-BN-Al composites were rapidly sintered using high-frequency induction heated sintering (HFIHS). The microstructure and mechanical properties (fracture toughness and hardness) were investigated by Vickers hardness tester and FE-SEM. The HFIHS method induced very fast densification, nearly at the level of theoretical density, and successfully prohibited grain growth, resulting in nano-sized grains. The fracture toughness was improved by consolidation facilitated by adding Al to the WC-BN matrix. The 5vol % Al added WC-BN composites showed higher mechanical properties (hardness and fracture toughness than the WC-BN composite.

Simultaneous Synthesis and Densification of Nanostructured NbSi2-SiC-Si3N4 by Rapid Sintering

2010 ◽  
Vol 123-125 ◽  
pp. 209-212
Author(s):  
In Jin Shon ◽  
Hyun Su Kang ◽  
Soo Kyung Bae ◽  
In Yong Ko
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Frequency ◽  
Induced Current ◽  
Simultaneous Application ◽  
Average Grain Size ◽  
Rapid Sintering ◽  
One Step ◽  
Simultaneous Synthesis ◽  
High Frequency Induction

A dense nanostructured 5NbSi2-SiC-Si3N4 composite was synthesized by the high-frequency induction-heated combustion synthesis (HFIHCS) method within 1 minute in one step from mechanically activated powders of 4NbN, NbC and 14Si. A highly dense 5NbSi2-SiC-Si3N4 composite with relative density of up to 98% was produced under the simultaneous application of a pressure of 80 MPa and the induced current. The average grain size and mechanical properties (hardness and fracture toughness) of the composite were investigated.

Effect of Work Material’s Hardness on Cutting Performance of TiAlN- and CrAlN-Coated Cutting Tools

2015 ◽  
Vol 656-657 ◽  
pp. 231-236
Author(s):  
Risa Koda ◽  
Hiroshi Usuki ◽  
Masahiro Yoshinobu ◽  
Kana Morishita ◽  
Shuho Koseki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Brinell Hardness ◽  
Cutting Tools ◽  
High Hardness ◽  
Superior Performance ◽  
End Mills ◽  
Arc Evaporation ◽  
Cutting Experiments ◽  
Cutting Speeds ◽  
Selection Of

For better selection of coated cutting tools, TiAlN (Ti50Al50N) and CrAlN (Cr50Al50N) coatings were deposited onto ball-nose and square end mills using arc evaporation, and their cutting performances were evaluated using steel workpieces of various hardnesses. In particular, cutting tests were performed on three types of workpieces, made from S50C, SKD61, and SKD11 steels, having Brinell hardness numbers of HB220, HRC40, and HRC60, respectively. The results of the cutting experiments were elucidated and discussed in terms of the mechanical properties and anti-oxidation resistances of the different coatings. The results revealed that TiAlN-coated square end mills at high cutting speeds (V = 200 m/min ) had superior performance when used on steels with high hardness (SKD11), whereas CrAlN-coated ball-nose end mills were superior when used on low hardness steel (S50C). Therefore, CrAlN-coated ball-nose end mills are concluded to be suitable for the machining of low hardness steels, whereas TiAlN-coated square end mills are preferable for the machining of high hardness steels (SKD11).

Mechanical properties of hot isostatically pressed Si3N4 and Si3N4/SiC composites

1993 ◽  
Vol 8 (3) ◽  
pp. 626-634 ◽  
Author(s):  
O. Unal ◽  
J.J. Petrovic ◽  
T.E. Mitchell
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Hardness ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Sic Whiskers ◽  
Sic Composites ◽  
Increasing Temperature

The mechanical properties of hot isostatically pressed monolithic Si3N4 and Si3N4−20 vol. % SiC composites have been studied by microindentation at temperatures up to 1400 °C. Indentation crack patterns and microstructures have been examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. It is shown that dense Si3N4 base materials can be synthesized by HIPing without densification aids. Both the monolithic Si3N4 and the Si3N4/SiC composites exhibit high hardness values which gradually decrease with increasing temperature. Both types of material show low fracture toughness values apparently because of strong interfacial bonding. On the other hand, the fracture toughness of the composite is about 40% higher than that of the monolithic material, due to the presence of the 20 vol. % SiC whiskers. A crack deflection/debonding mechanism is likely to be responsible for the higher toughness observed in the composite. High resolution electron microscopy shows that the grain boundaries in both samples contain a thin SiO2 layer.

Microstructural and Mechanical Properties Changes of Silicon Nitride Based Ceramic Using Post-Sintering Heat Treatment

2012 ◽  
Vol 727-728 ◽  
pp. 1085-1091
Author(s):  
José Vitor C. Souza ◽  
O.M.M. Silva ◽  
E.A. Raymundo ◽  
João Paulo Barros Machado
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Grain Size ◽  
Wear Resistance ◽  
High Hardness ◽  
Gas Pressure ◽  
Low Density ◽  
Nitrogen Gas ◽  
Structural Applications

Si3N4based ceramics are widely researched because of their low density, high hardness, toughness and wear resistance. Post-sintering heat treatments can enhance their properties. Thus, the objective of the present paper was the development of a Si3N4based ceramic, suitable for structural applications, by sintering in nitrogen gas pressure, using AlN, Al2O3, and Y2O3as additives and post-sintering heat treatment. The green bodies were fabricated by uniaxial pressing at 80 MPa with subsequent isostatic pressing at 300 MPa. The samples were sintered at 1900°C for 1 h under N2gas pressure of 0.1 MPa. Post-sintering heat treatment was performed at 1500°C for 48 h under N2gas pressure of 1.0 MPa. From the results, it was observed that after post-sintering heat treatment there was a reduction of α-SiAlON phase and increase of β-Si3N4phase, with consequent changing in grain size, decrease of fracture toughness and increase of the Vickers hardness.

scholarly journals Investigation of the Wear Performance of TiB2 Coated Cutting Tools during the Machining of Ti6Al4V Alloy

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2799
Author(s):  
Mohammad Shariful Islam Chowdhury ◽  
Bipasha Bose ◽  
German Fox-Rabinovich ◽  
Stephen Clarence Veldhuis
Keyword(s):  
Mechanical Properties ◽  
Tool Life ◽  
Cutting Tools ◽  
Chip Morphology ◽  
High Hardness ◽  
Ti6al4v Alloy ◽  
Wear Volume ◽  
Coating Delamination ◽  
Rough Turning ◽  
Coated Carbide

The machining of Ti6Al4V alloy, especially at low cutting speeds, is associated with strong Built-Up Edge (BUE) formation. The PVD coatings applied on cutting tools to machine such materials must have the necessary combination of properties to address such an underlying wear mechanism. The present work investigates and shows that TiB2 PVD coating can be designed to have certain mechanical properties and tribological characteristics that improve machining in cases where BUE formation is observed. Three TiB2 coatings were studied: one low hardness coating and two high hardness coatings with varied coating thicknesses. Wear performances for the various TiB2 coated carbide tools were evaluated while rough turning Ti6Al4V. Tool wear characteristics were evaluated using tool life studies and the 3D wear volume measurements of the worn surface. Chip morphology analyses were done to assess the in-situ tribological performance of the coatings. The micro-mechanical properties of the coatings were also studied in detail to co-relate with the coatings’ performances. The results obtained show that during the rough turning of Ti6Al4V alloy with intensive BUE formation, the harder TiB2 coatings performed worse, with coating delamination on the rake surface under operation, whereas the softer version of the coating exhibited significantly better tool life without significant coating failure.

scholarly journals KETANGGUHAN RETAK, KEKERASAN DAN KONDUKTIVITAS IONIK CSZ SEBAGAI ELEKROLIT PADAT SOFC DENGAN PENAMBAHAN CuO

2015 ◽  
Vol 16 (2) ◽  
pp. 85
Author(s):  
Ila Lailatun Sholihah ◽  
Dani Gustaman Syarif ◽  
Andhy Setiawan
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Ionic Conductivity ◽  
Solid Electrolyte ◽  
Optical Microscope ◽  
Crystal Structure Analysis ◽  
Cubic Phase ◽  
Hardness Tester ◽  
Lcr Meter

ABSTRAK KETANGGUHAN RETAK, KEKERASAN DAN KONDUKTIVITAS IONIK CSZ SEBAGAI ELEKROLIT PADAT SOFC DENGAN PENAMBAHAN CuO. Penelitian mengenai pengaruh penambahan CuO terhadap konduktivitas ionik, kekerasan dan ketangguhan retak CSZ sebagai elektrolit padat SOFC telah dilakukan. CSZ didoping dengan CuO dengan konsentrasi 0, 1, dan 2 % berat. Pelet CSZ yang didoping CuO dikompaksi dengan tekanan 4 ton/cm2 dan disinter pada suhu 1475 0C selama 3 jam. Konduktivitas ionik diukur dengan menggunakan alat LCR meter. Konduktivitas ionik CSZ dengan doping 0, 1, dan 2 % berat CuO adalah 0,063 mS/cm; 0,110 mS/cm; dan 0,082 mS/cm. Kekerasan dan ketangguhan retak diukur dengan metode vickers menggunakan alat uji keras Zwick. Hasil kekerasan vickers berturut-turut 9,9 GPa; 12,1 GPa; dan 10,5 GPa, dan ketangguhan retak berturut-turut 1,61 MPa/m0,5; 1,85 MPa/m0,5; dan 1,54 MPa/m0,5. Analisis struktur kristal dilakukan dengan menggunakan XRD. Hasil analisis menunjukkan bahwa keramik yang dibuat berfase kubik FCC. Analisis struktur mikro dengan menggunakan mikroskop optik menunjukkan bertambahnya ukuran butir dengan peningkatan 1% berat CuO. Secara keseluruhan penambahan CuO dengan konsentrasi 1% berat dapat memperbaiki sifat listrik dan sifat mekanik CSZ sebagai elektrolit padat. ABSTRACT FRACTURE TOUGHNESS, HARDNESS AND IONIC CONDUCTIVITY OF CSZ AS SOLID ELECTROLYTE WITH ADDITION OF CuO. A research on effect of CuO addition on ionic conductivity, hardness and fracture toughness of CSZ as solid electrolyte had been conducted. CSZ was doped with 0, 1, and 2 wt % CuO. Pellets of CuO doped CSZ had been prepared by pressing with pressure of 4 ton/cm2 and sintered at 1475oC for 3 hours. Ionic conductivity was measured by means of LCR meter. Ionic conductivity values of CSZ with doped 0, 1, and 2 % CuO were 0.063 mS/cm, 0.110 mS/cm, and 0.082 mS/cm. Hardness and fracture toughness were measured by vickers method using a hardness tester Zwick. The measured vickerss hardness were 9.9 GPa, 12.1 GPa and 10.5 GPa, and fracture toughness were 1.61 MPa/m0,5, 1.85 MPa/m0,5, and 1.54 MPa/m0,5. Crystal structure analysis was done by using XRD. The analysis result showed that the prepared ceramics have cubic phase of FCC. Microstructure analysis by using an optical microscope showed that grain size increased with the increased of 1 wt % CuO. The addition of CuO at conscentration of 1 wt % can improve the electrical and mechanical properties of CSZ as solid electrolyte.

scholarly journals Rapid Sintering and Synthesis of Nanocrystalline Ta-ZrO2 Composite

2020 ◽  
Vol 58 (11) ◽  
pp. 776-781
Author(s):  
Seong-Eun Kim ◽  
In-Jin Shon
Keyword(s):  
Fracture Toughness ◽  
Nanocrystalline Materials ◽  
Uniaxial Pressure ◽  
Pulsed Current ◽  
Mechanical Pressure ◽  
Hardness Tester ◽  
Rapid Sintering ◽  
Nanocrystalline Composite ◽  
Hip Joint Replacements ◽  
Short Time

ZrO<sub>2</sub> is a promising candidate for knee and hip joint replacements due to its excellent combination of low density, corrosion resistance and biocompatibility. Nevertheless, a low fracture toughness of pure ZrO<sub>2</sub> at room temperature limits its wider application in the industry. One of the most obvious ways to solve the problem is to add a reinforcing phase, to produce a nanocrystalline composite material. Nanomaterials have been widely studied in recent years because they can improve hardness and fracture toughness. To produce nanocrystalline materials, the pulsed current activated sintering method has the advantage of simultaneously applying mechanical pressure and pulsed current during sintering. As a result, nanocrystalline materials can be produced within a very short time. Ta and ZrO<sub>2</sub> nanopowders were mechanically synthesized from Ta<sub>2</sub>O<sub>5</sub> and 2.5Zr powders according to the reaction (Ta<sub>2</sub>O<sub>5</sub> + 5/2Zr → 2Ta + 5/2ZrO<sub>2</sub>). The synthesized powders were then sintered using pulsed current activated heating under 80 MPa uniaxial pressure within two minutes. Hardness and fracture toughness were measured using a Vickers hardness tester. The average hardness and fracture toughness of the nanocrystalline 2Ta-5/2ZrO<sub>2</sub> composite sintered at 1350 <sup>o</sup>C were 1008 kg/mm<sup>2</sup> and 10 MPa·m<sup>1/2</sup>, respectively. Both the hardness and fracture toughness of the composite were higher than monolithic ZrO<sub>2</sub>. The microstructure and phase of the composite was also investigated by FE-SEM and XRD.

AL TECH 609

Alloy Digest ◽  
1980 ◽  
Vol 29 (6) ◽  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Shear Strength ◽  
Elastic Limit ◽  
High Hardness ◽  
Heat Treating ◽  
Heavy Duty ◽  
Machine Parts ◽  
Specialty Steel

Abstract AL Tech 609 is a silicon type of shock-resisting tool steel containing small additions of chromium, molybdenum and vanadium to increase hardenability, decrease grain size and improve mechanical properties. Because of its high elastic limit and fair ductility at comparatively high hardness, it has the ability to withstand heavy shocks before bending or breaking. Its many uses include shear blades, heavy-duty punches, pneumatic tools for severe service and machine parts subject to shock. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: TS-363. Producer or source: AL Tech Specialty Steel Corporation.

Utilization of Light Microscopy for the Evaluation of Fracture Toughness of Cemented Carbides

2015 ◽  
Vol 647 ◽  
pp. 108-114
Author(s):  
Zbyněk Špirit ◽  
Antonín Kříž
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Metal Matrix ◽  
Computational Models ◽  
Cutting Tools ◽  
High Hardness ◽  
Cemented Carbides ◽  
Soft Matrix ◽  
Heat Loading ◽  
Indentation Methods

<span><p><span lang="EN-US">Cemented carbides belong among materials with high hardness and wear resistance even at temperatures around 700 °C. These properties are due to carbide composite structure which is formed mainly of tungsten carbide (WC) in combination with a metal matrix (usually cobalt). A synergistic effect </span><span><span lang="EN-US">that has a positive</span></span><span lang="EN-US"> <span>impact on the</span> <span>final properties</span></span><span lang="EN-US"> is obtained by the combination of hard carbides and a soft matrix</span><span><span lang="EN-US">.</span></span><span lang="EN-US"> </span><span lang="EN-US">The high hardness of the cemented carbides is associated with a decrease in fracture toughness which in the case of cutting tools is an important property. <span>It is therefore necessary to measure the value of fracture toughness and thus monitor the state of the material.</span></span><span lang="EN-US"> </span><span><span lang="EN-US">In practice,</span></span><span lang="EN-US"> <span>the fracture</span> <span>toughness</span> <span>of cemented</span> <span>carbides is usually tested by indentation</span> <span>methods</span> <span>of</span> <span>metallographic</span> <span>samples.</span> <span>Therefore, this work focuses on the comparison and optimization of computational models for determining fracture toughness using indentation methods.</span></span><span lang="EN-US"> </span><span><span lang="EN-US">Eight types of</span></span><span lang="EN-US"> <span>cemented carbides</span> <span>used</span> <span>for the manufacture</span> <span>of cutting tools were tested. F</span></span><span lang="EN-US">racture toughness of selected cemented carbides was measured after heat loading.</span></p>

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