Refined Solidification Structure and Improved Formability of A356 Aluminum Alloy Plate Produced using a High-Speed Twin-Roll Strip Caster

Abstract

An A356 aluminum alloy was cast into a 2 mm thick plate by a strip caster equipped with a pair of water-cooled rolls made of pure copper. The twin-roll cast plate exhibited fairly refined primary aluminum dendrite- and eutectic solidified structure. The estimated maximum cooling rate at the near-surface region of the plate is 4000 K/s. These values are significantly higher than the cooling rate for the permanent mold cast (2 K/s). The cast plate was cold-rolled and annealed into a 0.5 mm thick sheet. The resultant sheet was subjected to the 180° bending test. No cracking occurred in the twin-roll cast product. Improved formability is considered to be mainly due to the homogeneous distribution of fine Si particles.