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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 14 (1978), S. 93-97 
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Résumé Du cuivre pur (99.999 %) avec différentes tailles de grains a été déformé par laminage (réduction d'épaisseur entre 30 et 90%). Les courbes DSC mettent en évidence le dégagement d'énergie au cours de la recristallisation et montrent que l'énergie emmagasinée par déformation n'est pas sensible à la dimension des grains qui, au contraire, agit sur les paramètres cinétiques de la recristallisation. Dans une région étroite des taux de déformation on observe une variation brutale de l'énergie emmagasinée, de la température du pic DSC et de l'énergie d'activation de la recristallisation.
    Abstract: Zusammenfassung Reines Kupfer (99.999%) von sehr verschiedenen Korngrössen wurde durch Kaltwalzen deformiert (Herabsetzung der Stärke zwischen 30 und 90%). Die DSC-Kurven der Energieabgabe im Verlaufe der Rekristallisation zeigen, daß die durch Deformation entstandene Energiespeicherung gegenüber der Korngrösse nicht abhängig ist, jedoch die kinetischen Parameter der Rekristallisation beeinflußt. In einem engen Bereich der Deformationsgrössen kann eine jähe Änderung der gespeicherten Energie, der Temperatur des DSC-Peaks und der Aktivierungsenergie der Rekristallisation beobachtet werden.
    Notes: Abstract Pure copper (99.999 %) with various grain sizes was deformed by cold rolling (reduction in thickness 30–90%). DSC curves of energy evolution during recrystallization show that the stored energy of deformation does not depend on grain size, which on the contrary affects the kinetic parameters of recrystallization. Abrupt changes in stored energy, DSC peak temperature and activation energy of recrystallization are observed in a narrow range of deformation amounts.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Thermochimica Acta 13 (1975), S. 147-163 
    ISSN: 0040-6031
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 1997-04-01
    Description: Recent studies on albitite rocks located in the granodiorite complex of Central Sardinia have revealed that epidote has a widespread occurrence as a light rare-earth element (LREE)-bearing accessory common phase. Titanite has been recorded as a heavy rare earth element (HREE)-bearing mineral. The Hercynian granodiorite complex of Central Sardinia is composed chiefly of quartz, Ca-plagioclase, K-feldspar and biotite and of a wide variety of secondary assemblages, mainly allanite, titanite and zircon. Albitic plagioclase and quartz are the main mineral components of the albitites. Additional minerals include, besides allanite and epidote, a more calcic-plagioclase (oligoclase), K-feldspar, chlorite, titanite and more rarely muscovite. The mineral assemblages and REE-bearing minerals of albitites were analysed by wavelength dispersive spectrometry (WDS). Chemical data suggest that there is a near complete solid-solution between epidote and allanite whereas little variations in HREE of titanites were detected. In epidote-group minerals a pronounced zoning in REE was observed while titanite was recorded unzoned. Textural relations were studied by SEM to distinguish primary from secondary epidotes. Chemical criteria to recognize magmatic from alteration epidotes were also applied. The alteration epidotes mainly occur and generally originate from plagioclase alteration and from leaching of magmatic allanite. Comparison of textures using both the SEM technique and EPMA data showed that the characteristic ‘patchy zoning’, observed in epidotes, corresponds with different amounts of REE in these minerals.The schematic model proposed for the epidote-forming reactions during the metasomatic processes that affected the granodiorites involves: (i) the instability of the anorthitic component of plagioclase; (ii) the simultaneous formation of albite; (iii) the leaching of the magmatic allanite with a redistribution of REE in the epidotes of the albitites.
    Print ISSN: 0026-461X
    Electronic ISSN: 1471-8022
    Topics: Geosciences
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