Effect of mechanical alloying and preheating treatment on the phase transformation of the Al–Cu–Fe compacts annealed by microwave radiation

Abstract

The present study investigated the effect of mechanical alloying (MA) time, preheating and annealing process on phase and microstructural transformations in Al65Cu23Fe12 (at%) alloys. To release stresses, a part of milled powder was heated at 150 °C for 20 min and then raw compacts of the as-synthesized powders and preheated ones were prepared and heated at selected temperatures from 200 to 800 °C using microwave radiation. The results showed that with increasing the time of mechanical alloying process, the morphology of the particles changed and nanometer spherical particles were formed. Also, β-Al(Cu,Fe) solid solution phase was formed after 16 h of mechanical alloying. After 30 h of mechanical alloying, the quasi-crystalline phase did not form directly under the conditions employed in this work. Comparison of preheated samples with samples without preheating process showed that the quasi-crystal phase was formed at 300 °C for preheated samples, while the β phase was formed for samples without preheating process. The results of phase analysis also showed that β-Al(Cu,Fe) and θ-Al2Cu phases along with the quasi-crystalline phase are the main phases in the samples. The annealing process of the samples using microwave radiation leads to the formation of a quasi-crystal phase at temperatures and times much lower than other annealing methods.

Keywords

• Mechanical alloying
• Microwave radiation
• Quasi-crystal
• X-ray diffraction
• Annealing process