Microstructure Evolution during Solution Heat Treatment of Semisolid Cast 2024 Aluminum Alloy
The aim of this study is to determine the appropriate solution treatment temperature and time of semi solid 2024 Al alloy. Solution heat treatment at 450°C and 480 °C for various times, from 4 hours to 16 hrs, were applied followed by artificial aging at 220 °C for 1 hr. Microstructure of the semi solid cast 2024 aluminum alloy mainly showed globular grain structure which consisted of matrix-α (Al) and grain boundary (GB) - eutectic phases (α+Al2CuMg/Al2Cu). Eutectic GB phases was found to completely dissolved after solution heat treatment at 480°C for 14 hrs while sample solution treated at 450°C for the same time showed the existence of remaining GB phases. Prolonging heat treatment after 14 hrs at both temperatures resulted in the formation of coarse black particles at the grain boundaries which were identified as Mg2Si phases. Therefore the suitable solution treatment of the alloy in this study was at 480°C for 14 hrs.
Zhijiu Ai, Xiaodong Zhang, Yun-Hae Kim and Prasad Yarlagadda
S. Pannaray et al., "Microstructure Evolution during Solution Heat Treatment of Semisolid Cast 2024 Aluminum Alloy", Advanced Materials Research, Vol. 339, pp. 714-717, 2011