Threshold Stress for High-Temperature Deformation of Dispersion-Strengthened Alloys with Incoherent Dispersoids

Yoshida, Fusahito; Nakashima, Hisao

doi:10.4028/www.scientific.net/kem.171-174.261

Cited by 6 publications

(4 citation statements)

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“…disperzijsko oja anje. 4,5 Ono omogu ava da materijalu poboljšamo mehani ke karakteristike i da ih zadržimo pri visokim temperaturama.…”

Section: Methodsunclassified

“…In such dispersion-strengthened gold alloys the strengthening effect is obtained by dispersoids -dislocation interaction, whereby the dispersoids impede the dislocation motion. 4,5 They are fine-grained, have sufficient strength for crown and bridgework, but have to be melted and cast under protective gas atmosphere. 4 Melting of very pure components (Au= 99,99 w%, Pt= 99,99 w%, Ir= 99,99 w%, In= 99,99 w%, Rh= 99,99 w%, Nb= 99,99 w%) was performed at Zlatarna Celje d.d.…”

Section: Methodsmentioning

confidence: 99%

“…4,5 They are fine-grained, have sufficient strength for crown and bridgework, but have to be melted and cast under protective gas atmosphere. 4 Melting of very pure components (Au= 99,99 w%, Pt= 99,99 w%, Ir= 99,99 w%, In= 99,99 w%, Rh= 99,99 w%, Nb= 99,99 w%) was performed at Zlatarna Celje d.d. in vacuum induction melting furnace at vacuum p = 10 -2 mbar and temperature T = 1300°C.…”

Section: Methodsmentioning

confidence: 99%

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New gold dental alloy for metal-ceramic restorations

Rudolf¹,

Kramberger²,

Zupancic-Hartner

et al. 2006

SERBIAN DENT J

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Introduction: Porcelain to metal fused alloys with Au content are most frequently used in dentistry. Their characteristic is high biocompatibility and well fusion to ceramics. Aim of the study: The aim of this study was to present the procedure of production and technology of developing the new dental alloy with high gold content (Au). Materials and Methods: The dental alloy was melted and cast in a vacuum-induction melting furnace. Casting was followed by subsequent thermo-mechanical treatments (the procedures of profile and polish milling, and thermal treatment) and the cutting strips into regular shapes. Testing of the new Au dental alloy included an examination of alloy’s final condition. The measurement of hardness was carried out according to standard 6507-1:1998, and static tensile testing was performed for determination of the mechanical properties. Microscopic analysis of the dental alloy and the finished metal-ceramic bridge included an observation of the polished surface, and by performing qualitative and quantitative micro-chemical analyses. Results: The mechanical properties and hardness of new dental gold alloy was: Rp0.=630 [N/mm2], Rm =710 [N/mm2], A= 9%, 170 HV and CTE (25-600°C) about 14,55×10-6K-1. Macro-inspection of the finished metalceramic bridge showed that there was no porosity. However, during scanning electron microscopic examination, one of the tested sample shows porosity in one alloy region and in the ceramic layer. Detailed examination of the ceramic layer’s surface showed that there were two types of air or gas bubbles - larger with distinct bubbles (type I) and smaller with clearly porous microstructure (type II). Conclusions: According to the results of this study, it can be concluded that this new dental alloy from Zlatarna Celje satisfied all the required standards regarding mechanical properties and hardness. The application of new dental alloy with high gold content depends on the adequate technology when firing ceramics. It is necessary to obtain accurate oxidation temperature and cooling rates of metal-ceramic restorations because, otherwise, different defects may appear

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“…disperzijsko oja anje. 4,5 Ono omogu ava da materijalu poboljšamo mehani ke karakteristike i da ih zadržimo pri visokim temperaturama.…”

Section: Methodsunclassified

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

New gold dental alloy for metal-ceramic restorations

Rudolf¹,

Kramberger²,

Zupancic-Hartner

et al. 2006

SERBIAN DENT J

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“…Opisan model disperzijskega utrjanja s porami submikrometrske velikosti oziroma nanodelci je natančneje predstavil Srolovitz 18 , ki je za takšen DUM empirično podal mejno napetost s v potrebno za nadaljnje drsenje dislokacije preko prazninskega oziroma nanodelca; σ v naj bi bila za okoli 15% nižja od Orowan-ove napetosti σ OR . Kasnejše raziskave oprte predvsem na računalniške simulacije 19,20 so potrdile Srolovitz-ov model utrjanja s prazninami in določeno vrednost s v . Pri interpretaciji mehanizma utrjanja s prazninami 18 oziroma nanodelci pa je Srolovitz podal še ugotovitev, da je stopnja relaksacije linijske energije dislokacije na mejni površini matica/ praznina-nanodelec odvisna od časa delovanja zunanje napetosti.…”

Section: Mehanizmi Utrjanja Dentalnih Zlitin Iz Zlataunclassified

Nanotehnologija v postopkih precizijskega litja plemenitih zlitin

2022

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Precizijsko litje je postopek, ki temelji na ulivanju in strjevanju taline na »odstranjeni vosek«1. Prednosti precizijskega litja so visoka natančnost, gladkost površine ter celovitost izdelanih odlitkov, vse značilnosti pa se lahko uporabijo tudi v nanotehnologiji2. Tako izdelani odlitki iz zlitin kobalta, kroma, titana in srebra/zlata so že vrsto let poznani kot biokompatibilni materiali z izjemnimi elastičnimi lastnostmi3 in se uporabljajo na področjih ortopedije in zobozdravstva ter pri izdelavi mnogih medicinskih naprav4. Po drugi strani so danes zelo uporabljeni nanodelci plemenitih kovin in to predvsem na osnovi na zlata. Ti izkazujejo edinstvene fizikalne in kemijske lastnosti, kot so velika reakcijska površina, dobra absorpcija in prevodnost5. Ker zlitine na osnovi zlata oziroma srebra na makro-nivoju izkazujejo izrazito drugačne lastnosti kot nanodelci zlata in srebra na mikro nivoju, so slednji predmet mnogih novejših raziskav in posledično številnih novih aplikacij6,7,8. Vendar pa se večina raziskav na področju precizijskega litja plemenitih kovin ne osredotoča na nanotehnologijo, ki predstavlja velik raziskovalni potencial. Z uporabo nanotehnologije oziroma izboljšanega prezicijskega litja bi tako pridobili popolnoma nove lastnosti materialov, uporabne na številnih področjih s prvenstvenim ciljem v medicini. Predstavitev tega pristopa in kategorizacija teh postopkov je tako glaven cilj dela v katerem je predstavljen nov postopek izdelave zlitin in karakterizacijo njihovih lastnosti, kar predstavlja pomembno iztočnico za prihodnje raziskave.

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