Effect of cooling rate on the microstructure and thermal expansion properties of Al–Mn–Fe alloy

Abstract

Al–Mn–Fe alloy was prepared by traditional casting, injection casting, and melt spinning. The effect of cooling rate on the microstructure of alloy was studied. Results show that the phases in the alloy are the same for the three methods, including quasicrystal icosahedral phase (I-phase), Al6Mn phase, and Al phase. With the increase in cooling rate, the morphology of the I-phase changed from long strips to short rods and gradually to a daisy shape, and the content of the I-phase increased from 28 to 70%. Meanwhile, the morphology of the Al6Mn phase in the alloy changed from long bars to short rods, and the content decreased from 45 to 20%. Meanwhile, the thermal expansion coefficient of the alloy in the injection casting state is significantly reduced by about 15% at all temperature stages compared with that in as-cast state, and the results show that an appropriate cooling rate can improve the microstructure and properties of the alloy.

Keywords

• al–mn–fe alloy
• injection casting
• melt-spinning
• cooling rate
• quasicrystals
• coefficient of thermal expansion