Effect of microstructural complexity on the hot deformation behavior of aluminum alloy 2024

Powder metallurgy (P/M) aluminum alloy 2024 (Al-2024) reinforced with SiC whiskers is difficult to shape-form because of microstructural complexities introduced by rapid solidification and whisker additions. In the present investigation, four forms of Al-2024, viz. ingot, wrought, P/M, and P/M with 20 v/o silicon-carbide whiskers (SiCw) were examined to understand the influence of structural complexity on the hot deformation microstructural mechanisms. The analyses using the concepts of activation energy and dynamic stability criteria revealed that the safe hot working window of Al-2024 narrows as the microstructural complexity increases. This experimental observation was also explained on the basis of information theory. Safe processing window identified for the composite was validated using scaled-up extrusion experiments and the influence of processing conditions on microstructural control was demonstrated.