Microstructure and Mechanical Properties of Twin-Roll Strip-Cast Al-5.5Mg-0.02H Alloy Sheet

摘要

High-strength aluminum alloy sheets with high magnesium contents were fabricated by a strip caster equipped with an asymmetric nozzle, which has been proven to be effective for reducing surface defects and internal segregation. 4 mm thick as-cast sheets consisting of fine dendrites and minor Al_8Mg_5 segregation were hot-rolled successfully to 1 mm sheets and subsequently annealed at various temperatures. The sheet revealed the tensile strength and elongation of 306 MPa and 34%, respectively, when it was rolled at 250°C and subsequently annealed at 475 °C, which exhibits the feasibility of the practical application for autobodies. The observed mechanical properties were explained on the basis of the microstructural characteristics of the alloy sheets.