Creep behavior of additively manufactured high strength A205 aluminum alloy

Abstract

A20X, an additively manufactured high-strength aluminum alloy, was studied for its creep behavior at 200°C via the conventional uniaxial method and a novel, small-scale cantilever bending creep test, wherein the 2D strain field was measured using digital image correlation. A fine-grained microstructure with nano-scaled precipitates of Ω (Al-Cu-Ag-Mg) and θ′ (Al-Cu) leads to a stable microstructure and excellent mechanical properties at 200 °C in the solutionized and aged condition. The alloy displayed creep-resistant behavior with minimum strain rates of the order of 10−8-10−6 s−1 at 200 °C at 120-180 MPa. Uniaxial creep equivalence with bending creep was established, and the excellent creep resistance was attributed to the nano-scaled precipitates, which were shown to pin the dislocations effectively. Interestingly, a single bending test was able to effectively generate both tension and compression creep curves using small specimens, thereby establishing its suitability for near-net-shaped additively manufactured components.

Keywords

• A205
• Additive manufacturing
• DIC-augmented-bending creep
• High throughput creep testing
• Structure-property relationship for creep