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FIZIKA A 10 (2001) 4 , 191-202
 
DEPENDENCE OF MICROSTRUCTURE OF Al-44 at% Zn AND Al-48 at% Zn ALLOYS ON
TEMPERATURE
ŽELJKO SKOKO and STANKO POPOVIĆ
Physics Department, Faculty of Science, University of Zagreb,
Bijenička cesta 32,
HR-10002 Zagreb, POBox 331, Croatia
E-mail address: spopovic@phy.hr
Dedicated to Professor Kseno Ilakovac on the occasion of his 70th
birthday
Received 15 November 2001; Accepted 14 January 2002
Online 6 April 2002
The temperature dependence of microstructure of the title alloys was studied in situ by
XRD. Each alloy had been subjected to two different thermal treatments: (i) rapid
quenching from the solid-solution temperature, TSS, in water at room
temperature (RT) and ageing at RT (samples WQ) and (ii) cooling slowly from TSS
to RT and ageing at RT (samples SC). As the samples SC were closer to the equilibrium
state than the samples WQ, the microstructure of the two sets of samples dependeded on
temperature in a different way. The solid solution, aSS,
was formed at about 720 K for the samples SC, and at about 880 K for the samples WQ.
During the slow cooling to RT the samples SC and WQ behaved in a similar way. Instead of
the phase transitions expected according to the phase diagram, the following sequence of
transitions was observed for both alloys: a(M/b)+b(Zn) - a˘+b(Zn)+a(M/a˘,b) - aSS. A similar thermal
behaviour was also found for the Zn-rich alloys, Al-54 at% Zn and Al-62 at% Zn.
PACS numbers: 61.50.-f, 64.70, 64.75.-p, 64.75.+g, 65.70.+y
UDC 548.73
Keywords: Al-Zn alloys, solid solution, phase transition, phase diagram, X-ray powder
diffraction
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