Nanoobjects microscopy

Effect of alloying with transition metals on the age-hardening process of anomalous supersaturated solid solution of Al-Mg alloys
A.L. Berezina1, T.O. Monastyrska1, O.A. Molebny1, A.V. Kotko2
1 G.V. Kurdyumov Institute for Metal Physics of the NAS of Ukraine, Vernadsky Blvd. 36, Kyiv-142, 03680, Ukraine 
E-mail: monast@imp.kiev.ua
2 Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovskii Str. 3, Kyiv-142, 03680,Ukraine.

Decomposition processes of supersaturated solid solution of Al-Mg alloys alloyed with transition metals have been studied in the work.
The alloys were obtained by the melt-spinning method at the quenching temperature of 1000oС. The annealing at the temperature range of 300-4500С was carried out to study aging processes in the alloys. The structure and mechanical properties of the alloys were studied using transmission electron microscopy, X-ray diffractometry and hardness measurements. The temperature intervals of the phase transformations were determined by measuring the temperature coefficient of resistivity t=1/ 0 d/dT.
The study of the effect of additional alloying of rapidly quenched Al-Mg-Sc-Zr alloy with manganese and chromium on the kinetics and morphology of decomposition of supersaturated solid solutions showed that the introduction of Mn in the amount of  0.7% leads to strengthening of the alloy by  60% during aging. The thermal stability of the alloy increases to 400 - 450 ºС.
Simultaneous alloying of the alloy with manganese and chromium provides additional strengthening, but the thermal stability of the alloy decreases. The loss of the thermal stability of the alloy is due to the phase transformations in the primary particles of crystallization origin such as Al6(Mn,Cr). The obtained results indicate the inexpediency of simultaneous alloying of rapidly quenched Al-Mg-Sc-Zr alloy with manganese and chromium.