Predicting yield strengths of Al-Zn-Mg-Cu-(Zr) aluminium alloys based on alloy composition or hardness

摘要

A linear single variable model for describing precipitation heat treated Al-Zn-Mg-Cu aluminium alloy hardness and yield strength based on precipitate compositions was proposed. A concept composition model was developed based on the major alloying elements and the strengthening precipitate compositions, for the precipitation heat treatment condition. A Refined composition model was subsequently developed to account for the effect of minor alloying (Mn) and impurity elements (Fe, Si). Macro segregation of alloying elements had a significant effect on the results of the Refined composition model. Mechanical properties varied according to a simple linear relationship with the atomic fraction of the strengthening precipitate. The T6 and T73 hardness, and T6 yield strength were algebraically expressed, with linear relationships. The model describes existing yield strength data for Al-Zn-Mg-Cu aluminium alloys. The Refined composition model was also valid for predicting yield strengths of Al-Zn-Mg-Cu-Zr aluminium alloys in the T6 condition. (C) 2016 Elsevier Ltd. All rights reserved.