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.

On the quench sensitivity of 7010 aluminum alloy forgings in the overaged condition

“…The model, originally developed as Quench Factor Analysis (QFA) by Evancho and Staley [1] as a process-property model, was recently improved by Tiryakioğlu and Shuey to accommodate multiple quench precipitates [23][24][25], multiple properties [25], and multiple tempers [24]. Moreover, the improved model establishes process-structure-property relationships and uses thermodynamic data for certain coefficients.…”

Review of the Quench Sensitivity of Aluminium Alloys: Analysis of the Kinetics and Nature of Quench-Induced Precipitation

“…Besides continuous cooling, quenching to various isothermal soaking temperatures has also been frequently applied, again in combination with a subsequent property analysis, which allows isothermal time-temperature property diagrams to be derived, for instance [10,18,23,54]. In order to allow evaluation of continuous cooling basing on isothermal experiments, the quench factor analysis method was developed [20] and refined [47,48,52,[55][56][57][58].…”

Predicting the Response of Aluminum Casting Alloys to Heat Treatment

“…The kinetics parameter K 4 is the solvus temperature. However, recent findings suggest that the solution temperature would be a more accurate representation of K 4[26]. The kinetics parameter K 5 is the activation energy for aging the precipitates, and it was found to be 78 (kJ/mol) in the aging experiments, as shown in the following section.…”

“…By physical definition, the minimum value of the property that is achievable (σ min ) and the intrinsic property of the material (σ i ), are assumed to be the solutionized values. Thus, the final integrated equation can be described by three terms: the first term is controlled by the quenching process, the second term is controlled by the aging conditions and the final term is a material constant, as shown in Eq (26)…”