Naslov
Non-isothermal crystallization study of Metglas 2826 MB

Autori
Kurajica, Stanislav ; Šipušić, Juraj

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
MATRIB 2003 / Grilec, Krešimir - Zagreb : STSI, 2003, 117-122

Skup
International Conference Materials Tribology Processing MATRIB 2003

Mjesto i datum
Vela Luka, Hrvatska, 26.06.2003. - 28.06.2003

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Crystallization; Crystallization kinetics; Differential thermal analysis; Metglas 2826 MB; X-ray diffraction

Sažetak
Differential thermal analysis (DTA) and X-ray diffraction (XRD) were used to study the effect of non-isothermal heat treatment on devitrification behavior of the commercial Fe40Ni38Mo4B18 alloy (Metglas 2826 MB). In the temperature interval between 25 and 700°C the DTA curve of the studied metallic glass exhibit three exothermic peaks. Since the second peak is clearly a consequence of the two peaks superposition, the total number of transformations in this temperature interval is four. On the basis of DTA curve, the heat treatment in order to prepare samples for subsequent X-ray diffraction analysis has been scheduled. Using XRD the phases that crystallize during the exothermic processes are identified as FeNi ss and (Fe, Ni)23B6. The FeNi ss crystallize as primary phase followed by the additional FeNi ss and (Fe, Ni)23B6 crystallization. Finally, the decrease of boride and increase of FeNi ss XRD peaks intensity, points out to boride to FeNi ss transformation process. The mean grain sizes of the observed phases were calculated according to Scherrer formula. Very fine microstructure with the crystallite sizes of the order between 20 and 50 nm has been observed. The decrease of the (Fe, Ni)23B6 average grain size is observed between 580 and 700oC, i.e. the decrease of quantity of the (Fe, Ni)23B6 is followed by the reduction of the grain size. On the basis of presented facts it could be concluded that the Metglass 2826 MB is characterized by complex crystallization path. FeNi ss was found to be the primary phase to crystallize from the amorphous matrix. Primary FeNi ss crystallization is followed by additional FeNi ss and (Fe, Ni)23B6 crystallization. Finally, the additional amount of FeNi ss is formed from the (Fe, Ni)23B6. By the variation of annealing temperature different sample phase composition and microstructure could be produced. The activation energy for the crystallization of FeNi ss was determined in non-isothermal conditions using Kissinger equation and it yields 297&plusmn ; 4 kJmol-1.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

POVEZANOST RADA