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Selective-laser-melting, Al alloys, Dual-nanoprecipitation, Incoherent twin boundary with 9R phase, heating
Abstract:
A novel phenomenon of twin boundary-assisted dual-nanoprecipitation in a selective-laser-melted (SLM) Al alloy is systematically investigated. The dual-nanoprecipitation of Mg-Zn-rich η’ and Al-Sc-Zr-rich L12 phases is observed at a twin boundary. This twin boundary can be decomposed into incoherent twin boundaries with 9R phases, whereas provide nucleation sites for the dual-nanoprecipitation during in-situ heating at 120 °C. Such dual-nanoprecipitation is primarily driven by the Gibbs-free energy difference between the incoherent twin boundaries with 9R phases and the adjacent matrix. The results offer primary guidance to design a novel SLM Al alloy with dense twins and precipitations.