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Author Cziraki, A.; Gerocs, I.; Fogarassy, B.; Van Tendeloo, G.; Sommer, F.; Bakonyi, I.
Title Study of the thermal decomposition of melt-quenched Ni-rich metastable bcc and amorphous Ni-Zr alloys Type A1 Journal article
Year 1998 Publication International journal of non-equilibrium processing Abbreviated Journal Int J Non-Equilib Pr
Volume 10 Issue 3-4 Pages 265-282
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The phase transformation sequences during thermal decomposition are investigated for Ni-rich melt-quenched body-centred cubic (bcc) and amorphous Ni-Zr alloys. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) are used to determine the structure of crystallization products occurring after heating the melt-spun ribbon samples to various degrees of the phase transformation process monitored by differential scanning calorimetry (DSC). A single DSC peak is observed for both the bcc and amorphous Ni(91)Zr(9) alloys and a two-step process is indicated by DSC for the amorphous Ni(90)Zr(10) alloy. In the bcc-Ni(91)Zr(9) alloy which is actually a Ni(Zr) solid solution phase, the phase transformation starts with the precipitation of Ni(5)Zr crystallites followed, after a sufficient depletion of the matrix in Zr, by the subsequent transformation of the bcc-Ni(Zr) lattice to face-centred cubic (fcc) Ni. In the amorphous alloy of the same composition, the final products are fcc-Ni and Ni(5)Zr but at intermediate stages of the phase transformation, bcc-Ni(Zr) crystallites also appear. In the a-Ni(90)Zr(10) alloy the first DSC peak corresponds to the formation of the bcc-Ni(Zr) phase which then decomposes (second DSC peak) to the equilibrium phases fcc-Ni and Ni(5)Zr. Thus, in addition to the previous observation of the formation of the metastable bcc-Ni(Zr) phase by rapid quenching from the melt, here we present evidence that this phase can form also after partial crystallization of metallic glasses of appropriate chemical compositions.
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Corporate Author Thesis
Publisher AB Academic Publishers Place of Publication Bicester Editor
Language Wos 000075187300004 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1368-9290 ISBN (up) Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 2 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:104005 Serial 3341
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