Dumbre, J.Kairy, Shravan KAnber, ElafLangan, TimothyTaheri, Mitra L.Dorin, TBirbilis, Nick2023-03-150925-8388http://hdl.handle.net/1885/287088Scandium (Sc) containing Al-Si model alloys were heat-treated at various temperatures to determine the interaction between Si and Sc. The (Al,Si)3Sc phase was formed at ~350 °C and V-phase (AlSc2Si2) was observed to form at above ~450 °C, as determined from x-ray diffraction and selected area electron diffraction. Hardening of the alloys was observed due to the formation of coherent, nanoscale (Al,Si)3Sc precipitates; whereas significant softening was observed upon the formation of coarse V-phase. Herein, the V-phase is studied in detail and has for the first time been revealed to have a rod morphology. The Transmission electron microscopy (TEM) allowed for the determination of six new orientation relationships (ORs) with the α-Al matrix for the V-phase. Additionally, in situ TEM heating experiments at 550 °C revealed that the formation of V-phase occurs due to a nucleation and growth mechanism following the dissolution of Si particles and nanoscale (Al,Si)3Sc precipitates.his research used equipment funded by the Australian Research Council Grant (LE110100223). The authors are grateful to Clean TeQ Holdings Ltd., Australia for providing Al-Sc master alloys and acknowledge fi- nancial support through the ARC Linkage Project Scheme (LP160100104). Dr Thomas Dorin is the recipient of an Australian Research Council - Australian Discovery Early Career Award. The authors also acknowledge the use of the Centralized Research Facility (CRF) at Drexel University, Philadelphia, USA for in situ TEM experiments.application/pdfen-AU© 2021 Elsevier B.V.Metals and alloysMicrostructurePrecipitationTransmission electron microscopy (TEM)202110.1016/j.jallcom.2020.1585112022-01-09