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

College of Materials and Metallurgy, Northeastern University, Shenyang 110004, China
e-mail: guanrg@smm.neu.edu.cn

Received: 16 November 2011
Accepted: 27 April 2012

Abstract

A novel rheo-rolling process for producing A356 alloy sheet was developed. The influence of parameters on the microstructure of A356 alloy sheets was investigated. The eutectic fraction and primary α globule size increase with the increment in the roll speed. The globule size and eutectic fraction of A356 alloy sheet increase with the increment in the casting temperature. The primary α globule size decreases and the solid fraction increases with the increment in vibration frequency from 30 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-section size of 4 × 160 mm was prepared. The microstructure is mainly composed of fine spherical or rosette α globules, and the average α globule size is 20.5 μm. The ultimate tensile strength of the A356 alloy sheet was 260 MPa, and the elongation to failure was 7.9%, which were 2.5 and 3.7 times greater than those of the as-cast material.