Design and construction of a thixo forming unit and production of Al–Si alloys

In this study, a laboratory scale thixo forming unit was designed and constructed in order to carry out semi-solid process. Al–Si alloys were produced from the powders ground mechanically from ingots containing 5% Si on this unit. The powders were then cold pressed in order to produce cylindrical parts and thixo forming was applied to these cylindrical parts. Semi-solid processes were carried out at three different temperatures (580, 590 and 600 °C) for 1 and 2 min under 100 kN squeezing force. The results showed that spheroidisation tendency of the grains increased with increasing temperature. The grain size was also found to increase with increasing temperature. In addition, the period pressure applied was found to be an effective parameter in microstructural alterations. Thixo forming resulted in better microstructure with increasing pressure application period.