The effect of indirect forging pressure of wrought aluminium alloys on material properties by varying solid fraction using electromagnetic stirring

摘要

The rheoforming of Al7075 using the electromagnetic stirring (EMS) approach is demonstrated. The mechanical properties, chemical composition, and microstructural observations are performed on the produced samples. The rheo-slurry produced by EMS of a 60 A stirring current was forged for 20 s at temperatures of 625 ° C (solid fraction, f^sub s^=35 per cent) and 615 ° C (f^sub s^=50 per cent) under applied pressures of 170, 200, 220, and 250 MPa. The highest tensile strength of 404 MPa was recorded for a sample produced at a temperature of 615 ° C and a pressure of 220 MPa that underwent a T6 heat treatment. The sample produced at 625 ° C achieved its highest tensile strength for an applied pressure of 200 MPa and a T6 heat treatment. The improvement in the ductility observed in these samples is a result of the removal of a liquid phase that contains Cu and Si from the boundaries between grains of the pure α phase material. The elongation properties of the sample were investigated and correlated with the observed microstructures. [PUBLICATION ABSTRACT]