The Effect of Aging Processes on the Structure and Properties of Rapidly Solidified Al-Sc, Al-Zr and Al-Hf Alloys

Abstract

Structural states of Al-Sc, Al-Hf and Al-Zr alloys rapidly quenched from the liquid state have been studied. Features of structures in dependence on the nature of alloying elements, on the quenching temperature and the cooling rate by the crystallization of ribbons have been investigated. Fractal structures are formed by the quenching from the certain temperature-concentration region. The change of the morphology of structures has been researched during the aging process.

Decomposition Processes in the Anomalous Supersaturated Solid Solution of Binary and Ternary Aluminium Alloys Alloyed with Sc and Zr

“…high volume fraction and high precipitation density of the strengthening phase, as well as high thermal stability of the structure produced [3]. It was supposed that the high volume fraction would be provided during the decomposition of anomalously supersaturated solid solution obtained by the melt-spinning method; high precipitation density would be formed during continuous decomposition with the precipitation of particles which had a low activation energy for nucleation; thermal stability would be ensured due to a low surface energy and low mis t parameter of the matrix with the phase formed, as well as low solubility and low di usion coe cient of the alloying element in the matrix [4].…”

“…It was supposed that the high volume fraction would be provided during the decomposition of anomalously supersaturated solid solution obtained by the melt-spinning method; high precipitation density would be formed during continuous decomposition with the precipitation of particles which had a low activation energy for nucleation; thermal stability would be ensured due to a low surface energy and low mis t parameter of the matrix with the phase formed, as well as low solubility and low di usion coe cient of the alloying element in the matrix [4]. The formation of the L1 2 -ordered phase, isomorphic to the matrix, during the decomposition meets the abovementioned requirements.…”