Structural Evolution of Al-Cr Alloy during Processing |
| Journal |
Solid State Phenomena (Volume 138) |
| Volume |
Solid Phase Transformations |
| Edited by |
J. Čermák and I. Stloukal |
| Pages |
145-152 |
| DOI |
10.4028/www.scientific.net/SSP.138.145 |
| Online since |
March, 2008 |
| Authors |
Dalibor Vojtěch,
Alena Michalcová,
Pavel Novák
|
| Keywords |
Al-Cr Alloy, Aluminum, Phase Transformation, Powder Metallurgy, Rapid Solidification |
| Abstract |
Aluminium-chromium based alloys are promising candidates for manufacture of light
components exposed to elevated temperatures. The work describes properties of Al-6.0wt.%Cr-
2.1wt.%Fe-0.5wt.%Ti alloy. The rapidly solidified powder was prepared by the pressure nitrogen
melt atomization. The powder was then subject to heat treatment in order to investigate solid state
phase transformations. Compaction of the powder was carried out by hot extrusion after preheating
at 450 °C. Microstructure, phase composition and structural transformations on heat treatment were
investigated in the as-atomized powder, as well as in the as-extruded alloy. It is found that
metastable state of the rapidly solidified powder is characterized by presence of quasi-crystalline
phases and supersaturated solid solution. Heating before and during the hot extrusion induces
decomposition of the supersaturated solid solution and quasicrystalline to crystalline phase
transformations. The hot extruded alloy has a refined recrystallized structure that remains very
stable aven after long-term annealing at 400 °C. Mechanical properties of the extruded alloy are
discussed in terms of strengthening mechanisms. |
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