Influence of parameters on microstructure of A356 alloy sheetsprocessed by a novel rheo-rolling process

Abstract

A novel rheo-rolling process for producing A356 alloy sheet was developed. The influenceof parameters on the microstructure of A356 alloy sheets was investigated. The eutecticfraction and primary α globule size increase with the increment in theroll speed. The globule size and eutectic fraction of A356 alloy sheet increase with theincrement in the casting temperature. The primary α globule sizedecreases and the solid fraction increases with the increment in vibration frequency from30 Hz to 80 Hz. With a roll speed of 0.069 m.s^-1, a casting temperature of 660°C, and a vibration frequency of 80 Hz, A356 alloy sheet with a cross-sectionsize of 4 × 160 mm was prepared. The microstructure is mainly composed of fine sphericalor rosette α globules, and the average α globule size is20.5 μm. The ultimate tensile strength of the A356 alloy sheet was 260MPa, and the elongation to failure was 7.9%, which were 2.5 and 3.7 times greater thanthose of the as-cast material.