References of "Terziev, L"
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See detailPerformance characteristics of mill rolls from graphite chromium cast iron
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Breyer, J. P.

in Stal' (2000), 1

The main requirements for the development of a new grade for the later finishing section of the mill are : good oxidation and thermal behaviour, high wear resistance, good resistance to rolling incidents ... [more ▼]

The main requirements for the development of a new grade for the later finishing section of the mill are : good oxidation and thermal behaviour, high wear resistance, good resistance to rolling incidents. The approach of Marichal Ketin to improve the rolling performances in the last finishing stands is presented. The Hi-Cr cast iron possesses excellent wear resistance due to the presence of hard chromium carbides, but its thermal conductivity and sticking properties are fairly low. A graphite precipitation could contribute to an improvement in thermal conductivity and serve as lubricant preventing sticking. The new material, called graphitic chromium iron, shows good oxidation, wear and thermal behaviour allowing its use as work roll in the last stands of the finishing section of a HSM. In the as-cast condition, graphite precipitation in high Ni and Si chromium cast iron occurs at a temperature of 950 degrees C. Moreover, the amount and volume of free graphite may be increased by secondary graphite precipitation during suitable heat treatment. [less ▲]

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See detailApplication and performances of graphitic chromium cast iron rolls
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Breyer, J. P. et al

in Revue de Métallurgie [=Revue de Métallurgie. Cahiers d'Informations Techniques] (1999), 96(11), 1401-1411

The main requirements for the development of a new grade for the later finishing section of the mill are : good oxidation and thermal behaviour, high wear resistance, good resistance to rolling incidents ... [more ▼]

The main requirements for the development of a new grade for the later finishing section of the mill are : good oxidation and thermal behaviour, high wear resistance, good resistance to rolling incidents. The approach of Marichal Ketin to improve the rolling performances in the last finishing stands is presented. The Hi-Cr cast iron possesses excellent wear resistance due to the presence of hard chromium carbides, but its thermal conductivity and sticking properties are fairly low. A graphite precipitation could contribute to an improvement in thermal conductivity and serve as lubricant preventing sticking. The new material, called graphitic chromium iron, shows good oxidation, wear and thermal behaviour allowing its use as work roll in the last stands of the finishing section of a HSM. In the as-cast condition, graphite precipitation in high Ni and Si chromium cast iron occurs at a temperature of 950 degrees C. Moreover, the amount and volume of free graphite may be increased by secondary graphite precipitation during suitable heat treatment. [less ▲]

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See detailGraphitization in chromium cast iron
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Breyer, J. P.

in Mechanical Working and Steel Processing Conference Proceedings (1998)

Some trials with graphite Hi-Cr iron rolls have been done mainly in Japan, for the rolling of stainless steel. This material could lead to good compromise between oxidation, wear and thermal behaviour. By ... [more ▼]

Some trials with graphite Hi-Cr iron rolls have been done mainly in Japan, for the rolling of stainless steel. This material could lead to good compromise between oxidation, wear and thermal behaviour. By using thermal analysis and resistometry, the conditions for secondary graphite formation have been studied. The amount and volume of free graphite may be strongly increased by a suitable heat treatment, allowing a good thermal conductivity as well as high wear and mechanical properties. [less ▲]

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See detailDilatometric and calorimetric study of the graphitisation of high chromium cast iron
Terziev, L.; Lecomte-Beckers, Jacqueline ULg; Bojinov, V. et al

in Journal de Chimie Physique et de Physico-Chimie Biologique (1997), 94[5]

Cette étude est consacrée à la formation du graphite dans des fontes à haute teneur en chrome (8%) et spécialement à la détermination des conditions de formation de graphite secondaire par des traitements ... [more ▼]

Cette étude est consacrée à la formation du graphite dans des fontes à haute teneur en chrome (8%) et spécialement à la détermination des conditions de formation de graphite secondaire par des traitements thermiques adaptés. La solidification de la fonte étudiée a été examinée par analyse thermique différentielle (ATD). Les effets d'un traitement à haute température ont été examinés à la fois par calorimétrie et dilatomètre différentielle. Le graphite primaire se forme vers 950°C. Le graphite secondaire précipite sur le graphite primaire lors du traitement de déstabilisation de l'austénite à haute température. La forme et la quantité de graphite secondaire dépendent de la température de traitement. [less ▲]

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See detailStudy of graphite precipitation during heat treatment in chromium cast iron
Lecomte-Beckers, Jacqueline ULg; Terziev, L.

in Proceeding of the Annual Meeting of the SBM/NMVS (1997)

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See detailInfluence of creep on the microstructure of Zn-Al-Cu alloys aged at 250°C
Terziev, L.; Lecomte-Beckers, Jacqueline ULg; Wegria, J.

in Physica Status Solidi A : Applied Research (1995), 152[2]

This paper is a continuation of a microstructural study of ZA alloys subjected to ageing at different temperatures with subsequent creep at 20 and 120 °C. it was already established that the samples aged ... [more ▼]

This paper is a continuation of a microstructural study of ZA alloys subjected to ageing at different temperatures with subsequent creep at 20 and 120 °C. it was already established that the samples aged for one week at 100 and 250 °C show the slowest creep rate. Furthermore, the resuits obtained afler ageing at 250 °C are better than those obtained after ageing at 100 °C. In order to explain more correctly these resuits, the microstructure is studied after ageing at 250 oc and subsequent creep at room temperature under pressure at 100 MPa and at 120 °c under pressure at 40 MPa, on test samples broken after the respective creep. [less ▲]

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See detailMicrostructural study of a zinc-aluminium-copper alloy after thermal treatment at 100°C and creep
Terziev, L.; Lecomte-Beckers, Jacqueline ULg; Wegria, J.

in Zeitschrift für Metallkunde (1994), 85[9]

The creep behaviour of the ternary Zn—A1—Cu alloy after thermal treatment at ioo oc has been studied. The applied creep stress does flot modify clearly the transition phases (OL, T% ‘11m) appearing during ... [more ▼]

The creep behaviour of the ternary Zn—A1—Cu alloy after thermal treatment at ioo oc has been studied. The applied creep stress does flot modify clearly the transition phases (OL, T% ‘11m) appearing during isothermal ageing. During the creep test, the formation of an important density of defects resuits in the precipitation of T’ and O’ particles. The quantity of these phases depends on the creep conditions. [less ▲]

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See detailEtude des relations entre les microstructures obtenues par vieillissement isotherme et le comportement mécanique (fatigue, résilience) dans des alliages Zn-Al et Zn-Al-Cu
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Wegria, J.

in Revue de Métallurgie [=Revue de Métallurgie. Cahiers d'Informations Techniques] (1994), 91[5]

L’article présenté établit une corrélation entre le comportement mécanique (fluage, résilience) et les microstructures qui apparaissent au cours d’un traitement thermique isotherme (100 ou 250 °C) dans ... [more ▼]

L’article présenté établit une corrélation entre le comportement mécanique (fluage, résilience) et les microstructures qui apparaissent au cours d’un traitement thermique isotherme (100 ou 250 °C) dans des alliages Zn-Al et Zn-Al-Cu1. Le but est de mettre en évidence l’intérêt pratique des modifications structurales obtenues. On observe un meilleur résultat pour des échantillons vieillis pendant une semaine environ. La température de traitement la plus favorable est 250 °C. De plus, les alliages contenant du cuivre possèdent un meilleur comportement que les alliages binaires Zn-Al. [less ▲]

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See detailEvolution of microstructure during creep of thermally treated Zn-Al-Cu alloy
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Wegria, J.

in Proceedings of the 13th International Congress on Electron Microscopy (1994)

This paper illustrates the modifications of the structure induced by creep treatments. The aim of this study is to compare the evolution of the structure after creep tests on samples treated at 100°C and ... [more ▼]

This paper illustrates the modifications of the structure induced by creep treatments. The aim of this study is to compare the evolution of the structure after creep tests on samples treated at 100°C and 250°C. Creep tests have been carried out at 120°C with a tensile stress of 40MPa and at 20°C with a tensile stress of 100MPa. [less ▲]

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See detailTEM investigation of transition phases precipitation in ZA alloys after isothermal aging at 250°C and subsequent creep at high temperature
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Wegria, J.

in Materials Science Forum (Intergranular and Interphase Boundaries in Materials) (1993), 126-128

Transition phases occurring during isothermal aging at 250°C af ternary Zri-A1-Cu alloys are modlifîed after creep at high temperature. fle pressure applkd during creep leads to a high dertsity of clef ... [more ▼]

Transition phases occurring during isothermal aging at 250°C af ternary Zri-A1-Cu alloys are modlifîed after creep at high temperature. fle pressure applkd during creep leads to a high dertsity of clef ects which modifies the ndcrostructure. 11e trnsitiôn phases are studied by me ans of transmission electron microscopy and diffraction technique. Œ’r and phases pile up on dislocations. 11e reaction «s + £ 4 T +r 1$ accelerated and the transition T’ -. e’ is proxnoted by the defects. [less ▲]

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See detailElectron microscopical investigations of hexagonal phase precipitation in Zn---12 wt% Al---1 wt% Cu and Zn---27 wt% Al---2 wt% Cu alloys
Rachev, P.; Terziev, L.; Lecomte-Beckers, Jacqueline ULg et al

in Acta Metallurgica et Materialia (1991), 39(9), 2177-2182

In Zn---12 wt% Al---1 wt% Cu and Zn---27 wt% Al---2 wt%Cu alloys aged at 100° and 250°C the precipitation of h.c.p. phases was studied by means of transmission electron microscopy. The presence of the ... [more ▼]

In Zn---12 wt% Al---1 wt% Cu and Zn---27 wt% Al---2 wt%Cu alloys aged at 100° and 250°C the precipitation of h.c.p. phases was studied by means of transmission electron microscopy. The presence of the metastable ηm and ηx-phases was established using the Moiré pattern method. The ηm → η phase transition was observed. Screw dislocations are visualized in (114) with b logical and {220} in η phase precipitates by means of Moiré fringes. [less ▲]

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See detailPhase formation during aging of Zn-12% Al and Zn-27% Al alloys at 100°C.
Terziev, L.; Rachev, P.; Lecomte-Beckers, Jacqueline ULg et al

in Zeitschrift für Metallkunde (1990), 81[6]

The phase formation during ageing of ZrH2 wt% AI and Zna27 wt.% AI alloys at 100 O has been studied by means of transmission electron microscopy and electron diffraction. No formation of ellipsoidal ... [more ▼]

The phase formation during ageing of ZrH2 wt% AI and Zna27 wt.% AI alloys at 100 O has been studied by means of transmission electron microscopy and electron diffraction. No formation of ellipsoidal precipitates of GP 2 and c4 phase bas been observed. Precipitation of hexagonal phases occurs generally on account of the a phase. The <011> habitus plane of a new phase q has been found. The q phase has been distinguished from the metastable Qm using Moire patterns [less ▲]

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See detailEtude microstructurale des phases métastables dans les alliages Zn-Al
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Rashev, P. et al

in Journal de Microscopie et de Spectroscopie Electroniques (1989), 14[2]

Description de la précipitation complexe observée durant le vieillissement des alliages zinc-aluminium avec de petites quantités de cuivre et de magnésium

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See detailStudy of transition phases during isothermal aging at 250°C of Zn-27% Al alloy
Terziev, L.; Lecomte-Beckers, Jacqueline ULg; Rashev, P. et al

in Physica Status Solidi A : Applied Research (1989), 116[2]

Transition phases during isothermal aging of Zn-27% Al alloy at 250 °C are studied by means of transmission electron microscopy and diffraction technique. The supersaturated f.c.c. phase decomposes into ... [more ▼]

Transition phases during isothermal aging of Zn-27% Al alloy at 250 °C are studied by means of transmission electron microscopy and diffraction technique. The supersaturated f.c.c. phase decomposes into transition phases by formation of GP zones m. Formation of the rhombohedral phases r and of h.c.p. precipitates (m, x) is observed. [less ▲]

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See detailEtude microstructurale des alliages ZA12 et ZA27 au cours du vieillissement
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Rachev, P. et al

in Journal de Microscopie et de Spectroscopie Electroniques (1988), 13

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See detailAspects of the phase transformation during aging of Zn-11% Al and Zn-27% Al alloys
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Greday, T.

in Proceedings of the International Conference on Phase Transformation (1987)

The purpose of this work is to study the complex evolution observed during aging and the effect of alloying elements in ZA12 and ZA27. The results confirm the existence of the cellular reaction which ... [more ▼]

The purpose of this work is to study the complex evolution observed during aging and the effect of alloying elements in ZA12 and ZA27. The results confirm the existence of the cellular reaction which appears very quickly: after 1 h at 100 deg C the quench alpha sub 1 phase has nearly decomposed and the lamellae have begun to appear. Evidence of the second stage of aging is shown by the aged Zn--10.2% Al which exhibits fine precipitates alpha ' sub m FCC in alpha ' lamellae. When the aging time is increased diffusion of Zn inside these particles increases the difference in crystalline parameters leading to alpha ' HCP precipitates and finally to eta HCP. The aging is completed when the fine microstructure alpha ' sub m has disappeared leading is large globular grains of alpha and Beta [less ▲]

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See detailMicrostructural study of Zn-Al alloy
Terziev, L.; Rashev, P.; Lecomte-Beckers, Jacqueline ULg et al

in Proceedings of The 4th Physics and Chemistry of Solids, School-Symposium Physics of Metals, Polish Academy of Sciences, Institute for Low Temperature and Structure Research (1987)

It is well known that zinc-aluminium alloys posses very good mechanical properties. This is the reason why the investigation of their ageing characteristics is very important for the practice. Several ... [more ▼]

It is well known that zinc-aluminium alloys posses very good mechanical properties. This is the reason why the investigation of their ageing characteristics is very important for the practice. Several solid state reactions between alpha, beta, epsilon and T phases have been established for such materials alloyed with copper, but there has been no detailed on the formation, development and transformation of metastable phases into stable ones. This is exactly the aim of our investigation. [less ▲]

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See detailMicrostructural study of Zn-11% Al and Zn-27% Al alloys
Lecomte-Beckers, Jacqueline ULg; Terziev, L.; Wegria, J. et al

in Proceedings of the 25th Annual Conference of Metallurgists (1986)

Zinc-aluminium alloys with small amounts of copper and magneisum (ZA alloys) are used in a number of casting processes. They offer the foundry industry a family of zinc alloys with a wide range of ... [more ▼]

Zinc-aluminium alloys with small amounts of copper and magneisum (ZA alloys) are used in a number of casting processes. They offer the foundry industry a family of zinc alloys with a wide range of mechanical properties able to meet a large spectrum of performance criteria. However promising the characteristics of these alloys, microstructural studies of them are incomplete. It has been shown that copper additions to ZA alloys modify the number of the phase existing in the binary zinc-aluminium system as well as their transformation kinetics. Microstructural studies have shown not only the heterogeneity of the microstructure but also the presence of a zinc-rich metastable phase and the evolution of the composition of the ternary phase Zn-Al-Cu (T) during ageing. This situation is not surprising as several studies have shown the existence of metastable phases in the binary system Al-Zn with high aluminium content. the complexity of the microstructure leads us to search further for a better understanding of the binary Zn-Al alloys, with Al contents corresponding to ZA 12 and ZA 27 wihout any Cu and Mg, in order to precise about the complex evolution to stable phases observed in these alloys. [less ▲]

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