Production of High Strength Al—Mg—Sc Alloys by PM

Abstract

Powders of Al–Sc and Al–Mg–Sc alloys with up to 2 wt-%Sc content were produced by high energy inert gas atomisation. Microstructure and properties of the powders were compared and discussed. The powders were encapsulated, precompacted, evacuated, and consolidated by hot extrusion at 300°C. Chemical analysis was performed by the energy dispersive X-ray technique. Artificial aging was applied to the extruded materials. A final artificial aging treatment of 1 h at 310°C was found to be sufficient to produce maximum hardness of 66 HV10 after homogenisation at 635°C for 1 h. The results of microstructural characterization and mechanical properties were presented. Both yield and tensile strength increase with increasing scandium content. The binary alloy containing 2%Sc has a yield strength of 238 MPa and a tensile strength of 325 MPa. The addition of 5·5%Mg to this alloy raises the yield strength to 567 MPa and the tensile strength to 595 MPa. PM/0789