Influence of annealing parameters on the mechanical properties of heterogeneous lamella structured 5083 aluminum alloy

It has long been a research goal to obtain both high strength and ductility in structural materials. As the most important structural materials, metals and alloys are either strong or ductile, but seldom maintain both characteristics at the same time. After decades of attempts, extraordinary high strength has been achieved by involving nano- or ultrafine-grained structure. However, the ductility of these materials is relatively low. In the recent years, heterostructured materials have been demonstrated to possess superior combinations of strength and ductility, which are attributed to the hetero-deformation induced (HDI) strengthening and work hardening. The HDI hardening in previous studies is mainly caused by soft / hard domain boundaries. Here we report a heterogeneous lamella structure (HLS) in 5083 aluminum alloy fabricated by rolling and partial annealing. Superior combinations of strength and ductility have been achieved in the HLS Al-5083 through various annealing times and temperatures in this paper. Based on EBSD and TEM analysis, HDI hardening is an important reason for the excellent combination of strength and ductility. And soft / domain boundary hardening, and precipitation hardening are revealed as two important components of HDI hardening in Al-5083. These findings elucidate the HDI hardening mechanism in Al-5083 alloy, which will help us design the heterostructure of Al-5083 for engineering applications.

1. US Army Research Office - W911 NF-12-1-0009
2. State of North Carolina and the National Science Foundation - ECCS-1542015