Effects of Mn Concentration on Grain Boundary Pinning of 5083 Aluminum Alloy

Superplastic deformation has a significant industrial application value due to the large elongation, which allows manufacturing parts with complex geometries but happens at elevated temperatures and low strain rates. Therefore, it requires alloys with fine grain size but whose grains tend to grow at processing temperatures. Second-phase particles can promote grain boundary pinning to keep a fine grain size structure during superplastic forming. In 5083 aluminum alloy, Al₆Mn particles make grain boundary pinning. There are two types of 5083 aluminum alloy: conventional with manganese range from 0.4 to 1.0 wt.% and superplastic with manganese between 0.64 and 0.86. It was observed in bibliographic research that the 5083 superplastic has a higher chemical concentration of manganese than the conventional one. However, no references were found covering manganese concentration in grain size stability. This work shows grain size evolution at a constant temperature of 5083 alloys with different manganese concentrations. This work indicates that the manganese substantially impacts grain boundary pinning when the chemical composition is between 0 and 0.6 wt.%. No significant effects were observed for Mn concentrations higher than 0.6%".

Keywords:
Aluminum Alloys; superplasticity; AA 5083; grain boundary pinning