Comprehensive quality index and map of cast Al alloys according to artificial aging heat treatment conditions using TOPSIS and multiple regression analysis and determination of reasonable heat treatment condition

Abstract

Some quality indices such as Q, QR, QC and Q0 have been used to evaluate quality level of cast aluminum alloys (Al alloys) based on tensile properties, and quality map has been used to intuitively evaluate the quality level based on the quality index. The previous quality indices and maps lack in evaluating the quality level throughout all the tensile properties, comprehensively. On the other hand, they don’t directly show the quality level according to artificial aging heat treatment condition, while they show the quality level according to the tensile properties. We propose a method to develop comprehensive quality index and map of cast Al alloy according to artificial aging heat treatment condition by using technique for order preference by similarity to ideal solution (TOPSIS) and multiple regression analysis. Moreover, we propose a method to determine a reasonable heat treatment condition by using extremum principle and grid search method. To illustrate the effectiveness, the methods are applied to the cast Al alloy A357. The proposed methods could be widely used to evaluate the comprehensive quality level of the cast Al alloys, and optimize the heat treatment condition.