Riei Ichikawa1 and Kenji Miwa1
1Department of Metallurgical Engineering, Nagoya Institute of Technology, Nagoya
The apparent viscosity and the microstructure of a partially solidified hyper-eutectic Al-Mn alloy in a pasty state under stirring were examined, along with aggregation phenomena of the primary intermetallic compounds. Specimens were mechanically stirred with a rotor at 0.33∼8.33 s-1 during continuous cooling from the liquid state, and the apparent viscosity was measured as the value of torque. The value of torque increased with the increase of fine Al4Mn crystals during cooling from the liquidus temperature to the peritectic temperature, and the value decreased steeply through the peritectic temperature and then became nearly constant because of the coarse Al6Mn crystals having appeared in the peritectic. Finally, it increased sharply with the advance of solidification at the eutectic temperature at which the solidification finished. It was observed that part of the Al6Mn crystals were aggregated by stirring and the aggregate coarsened with increasing revolutions of stirring.
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