Iron-bearing intermetallic phases formed during solidification of Al-Si casting alloys are known for having detrimental effect on their mechanical properties. This is particularly the case of the β-Al5FeSi phase which precipitates as thin and extended plates. Many researchers already studied the factors that could influence the formation of this phase and in most cases it has been concluded that low-level additives (e.g. manganese) may lead to the replacement of the beta phase with other intermetallics that are less harmful because of being more compact.In this preliminary work, differential thermal analysis (DTA) was used to study the effect of cooling rate (0.2-40 °C/min) on beta phase formation in Al-6.5Si-1Fe alloy. The effect of cooling rate on the characteristic temperature for phase changes was described and compared to literature information. The beta phase was then characterized using scanning electron microscopy and X-ray tomography. Metallographic analysis showed the phase morphology was heavily affected by the cooling rate, and parameters to quantify this have been selected and measured. Moreover, observation also revealed that some alpha phase precipitates at low cooling rate.
|Number of pages||5|
|Journal||Transactions of the Indian Institute of Metals|
|Publication status||Published - Dec 2012|
- Beta intermetallic phase
- Cooling rate
- X-ray tomography