Microstructure and Properties of Al-Zn-Mg-Cu-Mn In Situ High Strength Alloy

Abstract

Al-Zn-Mg-Cu alloy containing 2%Mn was made using spray forming method and hot extrusion. XRD, OM, and SEM were used to investigate the microstructure. Results showed that after being hot extruded and solid solution treated, the Al alloy matrix had uniformly fine recrystallized grain with an average size of 8μm. The particles of MnAl6 were formed during the spray forming process and distributed along the grain boundary. Deformation and spheroidization of MnAl6 particles were occurred during post hot extrusion and solid solution treament, which would be benefit to the improvement of toughness of Al alloy. When aged at the T6 conditions, the tensile strength of the Al alloy was increased up to 775MPa with the elongation of 4.3%, the fracture surface consisted mainly of dimples with a size lower than 500nm.