Precipitate effects on the mechanical behavior of aluminum copper alloys: Part I. Experiments

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2005-03, Vol.36 (3A), p.749-761
• Main Authors: Sehitoglu, H, Foglesong, T, Maier, H J
• Format: Article
• Language: English
• Subjects: Aluminum alloys; Anisotropy; Heat treating; Mechanical properties; Microstructure; Precipitation hardening
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-005-0190-4

This article focuses on understanding the mechanical behavior of precipitation-hardened alloys by studying single and polycrystalline deformation behavior with various heat treatments. Aluminum-copper alloys are the focus in this work and their changing stress-strain behavior is demonstrated resulting from the different hardening mechanisms brought about by the various precipitates. Extensive transmission electron microscopy investigations facilitated the interpretation of the stress-strain behavior and the work hardening characteristics. The use of both single and polycrystals proved valuable in understanding the role of anisotropy due to crystal orientation vs precipitate-induced anisotropy. The experiments show that precipitation-induced anisotropy could offset the crystal orientation anisotropy depending on the orientation. This is clearly demonstrated with similar [111] and [123] behaviors under 190 °C and 260 °C aging temperatures. Experiments on pure aluminum crystals are also provided for comparison and understanding the crystal anisotropy in the absence of precipitates. Part I of this article will focus on experiments, and part II will describe the modeling of the effect of different metastable phases in the matrix acting as barriers to dislocation motion. [PUBLICATION ABSTRACT]