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Titolo:
Synthesizing of nanocomposite WC/MgO powders by mechanical solid-state reduction and subsequent plasma-activated sintering
Autore:
El-Eskandarany, MS; Omori, M; Konno, TJ; Sumiyama, K; Hirai, T; Suzuki, K;
Indirizzi:
Al Azhar Univ, Min & Petr Engn Dept, Fac Engn, Cairo 11371, Egypt Al AzharUniv Cairo Egypt 11371 Engn Dept, Fac Engn, Cairo 11371, Egypt Tohoku Univ, Inst Mat Res, Dept High Temp Mat Sci, Sendai, Miyagi 9808577,Japan Tohoku Univ Sendai Miyagi Japan 9808577 Sci, Sendai, Miyagi 9808577,Japan Tohoku Univ, Inst Mat Res, Dept Chem Phys Noncrystalline Mat, Sendai, Miyagi 9808577, Japan Tohoku Univ Sendai Miyagi Japan 9808577 at, Sendai, Miyagi 9808577, Japan Sumitomo Met Ind Ltd, Adv Mat Res, Amagasaki, Hyogo 6600891, Japan Sumitomo Met Ind Ltd Amagasaki Hyogo Japan 6600891 , Hyogo 6600891, Japan
Titolo Testata:
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
fascicolo: 1, volume: 32, anno: 2001,
pagine: 157 - 164
SICI:
1073-5623(200101)32:1<157:SONWPB>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
ALLOY POWDERS; TOUGHNESS; CARBIDE; WC;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
22
Recensione:
Indirizzi per estratti:
Indirizzo: El-Eskandarany, MS Al Azhar Univ, Min & Petr Engn Dept, Fac Engn, Cairo 11371, Egypt Al Azhar Univ Cairo Egypt 11371 n, Cairo 11371, Egypt
Citazione:
M.S. El-Eskandarany et al., "Synthesizing of nanocomposite WC/MgO powders by mechanical solid-state reduction and subsequent plasma-activated sintering", MET MAT T A, 32(1), 2001, pp. 157-164

Abstract

A ceramic/ceramic nanocomposite powder of WC/MgO has been fabricated by high-energy ball milling a mixture of elemental Mg and powders of C with WO3 under an argon gas atmosphere at room temperature, During the early stage of milling (at 1.8 ks), the WO3 and C powders are embedded into the soft matrix of Mg (the reducing agent) particles to form coarse composite powders of the reactant materials. Increasing the milling time (to 22 ks) leads to the formation of fresh active surfaces of Mg, which have a high reducing potential and react with the WO3 in a typical oxidation/reduction reaction. Atthe end of this stage (at 43 ks), the Mg powders are oxidized to MgO, whereas the WO3 is reduced completely to metallic W. During the last stage of milling (86 to 173 ks), a solid-state reaction takes place between W and theunreacted C powders to yield nanocomposite WC/MgO particles. This end-product was consolidated in vacuum at 1963 K with a pressure of 19.6 to 38.2 MPa for 0.3 ks, using a plasma-activated sintering (PAS) method. The sinteredsample is fully dense (above 99.5 pet of the theoretical density) and contains nanocrystalline grains of less than 50 nm in diameter. This fine grainstructure offers an opportunity for the composite material to combine highvalues of two opposite properties, i.e., hardness and fracture toughness (K-c), of 15 GPa and 14 MPa rootm, respectively. Here, we propose this nanocomposite material for a wide range of industrial applications, including tips for cutting tools and tips for oil drilling equipment.

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Documento generato il 10/07/20 alle ore 12:27:42