Effect of Sc addition on the microstructures and age-hardening behavior of an AlCuMgAg alloy

Publication date: Available online 18 April 2019Source: Materials Science and Engineering: AAuthor(s): Song Bai, Xinlei Yi, Guanhua Liu, Zhiyi Liu, Jian Wang, Juangang ZhaoAbstractThe association between small Sc addition and different precipitates in an AlCuMgAg alloy is investigated in the present work to explain the Sc-dependent microstructural evolution during extended aging at 180 °C. The age-hardening capacity and the strength properties of AlCuMgAg alloy are found to be degraded by 0.32 wt% Sc addition. This negative effect of Sc is directly associated with the formation of Al8Cu4Sc intermetallics, which consumes the available Cu solutes for Ω precipitation and hence contributes to the slower Ω nucleation and resultant lower plate number density. Addition of 0.32 wt% Sc to the studied AlCuMgAg alloy also facilitates the rapid growth of S precipitates and induces a rapid lengthening of Ω phase during extended aging. In addition, no distinct grain refinement can be observed with 0.32 wt% Sc addition.
Source: Materials Science and Engineering: A - Category: Materials Science Source Type: research