Effect of Precipitation During Quenching on the Prediction of the Mechanical Properties of Al-5 Pct Cu Alloy After T6 Treatment

The mechanical properties of Al-5 pct Cu cast alloy, one of the heat-treatable aluminum alloys, depend on the quenching rate and aging conditions. The effect of precipitation during quenching cannot be ignored for large and thick-walled components, although it is generally assumed that no precipitates form during cooling. In this article, a non-isokinetic model, considering the strengthening effects of precipitation during quenching and aging, was proposed to describe the evolution of minimum strength based on fully precipitating tests and transmission electron microscopy observations. Moreover, a comprehensive quench factor analysis, integrated with the non-isokinetic model, was conducted for the Al-5 pct Cu cast alloy using isothermal quench tests. Finally, the integrated model of the mechanical property was validated under various quenching conditions, including water at 353 K (80 °C), air at room temperature and furnace cooling. It was shown that the prediction can be extended to an 85 pct loss of property.