Abstract
Scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS) were used to observe intergranular and intragranular β-phase (Al3Mg2) formation and growth in as-received sample and long-term (~ 1 year) thermally treated samples of 5083-H131 alloy. Rod-shaped and equiaxed particles rich in Mn, Fe, and Cr were present in the as-received
and heat treated samples. The β-phase precipitated along grain boundaries as well as around and between preexisting Mn-Fe-Cr rich particles. The measured thickness of β-phase along grain boundaries was lower than Zener–Hillert diffusion model predicted value and the potential reasons were theoretically analyzed. Dislocation networks, grain boundaries, and different preexisting
particles were observed to contribute to Mg diffusion and β-phase precipitation.
