Abstract
The present work is concerned with the precipitation kinetics of Al-Ge (Si) alloys with different amounts of Ge and Si. Continuous heating and isothermal dilatometry are used successfully to identify the formation and dissolution of Ge or Si-Ge precipitates. Differential Scanning Calorimetry on the same samples confirms the temperatures of precipitation and dissolution. The formation and dissolution of precipitates are studied after different thermal histories. The precipitation kinetics of AlGe1 samples is significantly slower than that of alloys containing more Ge. The apparent activation energy determined from thermal expansion peaks during heating is 20 % smaller for AlGe3 than for AlGe1.

Key words
Al alloys, precipitation kinetics, thermal expansion, differential scanning calorimetry, isothermal dilatometry

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