Modeling Quench Sensitivity of Aluminum Alloys for Multiple Tempers and Properties: Application to AA2024

Abstract

Quench factor analysis (QFA) was developed to predict the change in certain properties, such as yield strength, hardness, electrical conductivity, etc., with how the material cools from solution treatment temperature during quenching. This method necessitates that a set of coefficients be developed by laboratory testing for a particular alloy in a given temper. In the original QFA, these coefficients have been developed independently for each physical property of each temper that might be produced from the same alloy. However, properties used commonly to assess quench sensitivity, e.g., electrical resistivity, hardness tests, tensile tests in different directions, etc., all respond to the same physical change during quench: loss of solute caused by the precipitation of quench precipitates. The QFA method has been modified to handle multiple properties and multiple tempers. The new method allows multiple C-curves for multiple phases and/or nucleation mechanisms for quench precipitates. The advantages of this method include better statistical resolution when fitting multiple data concurrently and possible substitution of a cheaper test for the property and temper of interest. The use of this approach is demonstrated on data sets for aluminum alloy 2024 within this study.