Influence of Natural Aging on Artificial Age Hardening of an Aluminum Cast Alloy

Abstract

 The natural age hardening and its influence on age hardening of Al11Si0.3Mg cast alloy were investigated by hardness measurement. Differential scanning calorimetry (DSC) and TEM analysis are used to analyze the age precipitation behaviors. The artificial age hardening response is significantly influenced by natural aging time before artificial aging. There is a harmful effect for natural aging 5-30 h on artificial age hardening response. TEM and DSC analysis results show that the precipitation of β″ and/or β′ phases during artificial aging is influenced obviously by natural aging time before heating. The relationship of artificial age hardening response with the precipitation of β″ and/or β′ phases has been discussed.