Computational Thermodynamics Characterization of 7075, 7039, and 7020 Aluminum Alloys Using JMatPro

Report No. ARL-TR-5660
Authors: John F. Chinella; Zhanli Guo
Date/Pages: September 2011; 78 pages
Abstract: Thermodynamics-dependent microstructure, phase, and physical model predictions of material characteristics are demonstrated for aluminum alloys 7020 (Al-4.5Zn-1.2Mg), 7039 (Al-4.0Zn-2.8Mg), and 7075 (Al-5.6Zn-2.5Mg-1.6Cu) by direct application of Sente Software Ltd.'s Java Materials Program (JMatPro) mesoscale computation materials engineering software. JMatPro reveals phase constitutions as a function of input composition, temperature, and time; with the use of material property databases and physical models, it calculates temperature-dependent physical and mechanical properties. The JMatPro material property software provides better and more rapid understanding of materials during research, processing, product manufacture, and service. In this report, JMatPro reveals how structural and protection materials may meet design requirements for low cost, fabricability, and durability. With secondary application, the elastic bulk moduli for intermetallic phase inclusions derived from Gibbs energy by JMatPro are used to predict the maximum levels of microscale shear stresses under hydrostatic pressure. With comparison to conditions known to cause incipient spall in 7020 alloy, the levels of microscale shear stress around intermetallic inclusions are shown to equal or exceed the level of Von Mises calculated shear yield strength of 7020 alloy, revealing that deformation may occur during high load spall events, even at the initial stages of compression.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2011