Spark plasma sintering of aluminum powders prealloyed with scandium additions

The objective of this research was to commence work on the spark plasma sintering (SPS) of Al-Sc alloys in an effort to develop fundamental data in this area. In this precursory study, a series of binary systems containing 0.1 to 0.4 wt% Sc were processed in laboratory and industrial-scale equipment. Data revealed that all powders were responsive to SPS in both scenarios and that sintering temperature was a variable of critical importance. Hardness of as-sintered products scaled directly with Sc concentration but varied inversely with SPS temperature owing to in-situ aging of the raw powders. Hardness losses could be recovered through a post-SPS heat treatment into the T6 condition. Industrially processed slugs of Al-0.4Sc-T6 exhibited full densification and offered the highest hardness (786+/−8 MPa). This was accompanied by a nominal tensile yield strength of 197 MPa, UTS of 226 MPa and tensile ductility of 11%.