Naslov
Temperature dependence of microstructure of Al-Ag- Zn alloys

Autori
Popović, Stanko ; Skoko, Željko ; Štefanić, Goran

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
11th European Powder Diffraction Conference Abstracts / - Varšava : Conference Engine pielaszek research, 2008, 114-115

ISBN
83-89585-22-7

Skup
11th European Powder Diffraction Conference

Mjesto i datum
Varšava, Poljska, 19.09.2008. - 22.09.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
XRD; alloys; phase transitions; Al-Zn-Ag

Sažetak
Al-rich Al-Ag-Zn alloys, quenched to RT from a temperature, Tt, higher than the solid-solution temperature, Tss, contained GP zones, as proved by XRD and TEM. GP zones grew during ageing, remaining fcc and coherent with the Al-rich α - phase (fcc). In parallel, metastable precipitates, ε ´ (hcp), were formed by discontinuous nucleation and by a direct transition from GP zones. The unit-cell parameters of ε ´ and of the equilibrium phase, ε (hcp), formed in the alloys slowly cooled from Tt to RT, depended on the solute content. The quenched and prolongedly aged alloys, being two- phase systems, α + ε ´, were studied in situ at high temperature. The following was observed: an initial lattice strain annealing, an anisotropy of thermal expansion of ε ´, a gradual dissolution of ε ´ in the α -phase above 500 K, the formation of solid solution. Tss depended on the alloy composition. On cooling, a temperature hysteresis was noticed in reversal changes. The dependence of unit-cell parameters of ε ´ on temperature during cooling was different from that during heating. After the heating and cooling cycle, unit-cell parameters of the precipitates were close to those of the equilibrium phase, ε .

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA