Sensitivity Analysis of Heat Treatment Parameters on Cylinder-head Aluminum Alloy Properties by Regression Method

In this article, by the regression analysis, suitable patterns for the hardness and the microstructure of the cylinder-head aluminum alloy have been presented. Objective functions were the hardness, the phase size and the spherical degree and variables were selected as the temperature and the time for the solution and ageing, in experiments. Results showed that the highest hardness (164 VHN) obtained when the sample was heated at 510°C for 300 minutes; then, aged for 360 minutes at 175°C. The optimal heat treatment was determined to achieve the smallest value of the phase area, as well as a higher amount of spherical phases. Results of the regression analysis demonstrated that the ageing time was more effective than the temperature in hardness variations, and the solution temperature was more important than the ageing temperature.