Evidence that the liquid structure affects the nucleation of the primary metastable L12-Al3Zr in additive manufacturing. (15th March 2023)

• Record Type: Journal Article
• Authors: Buttard, Maxence; Martin, Guilhem; Harrison, Patrick; Rauch, Edgar F.; Chéhab, Béchir; Jarry, Philippe; Blandin, Jean-Jacques; Donnadieu, Patricia
• Is Part Of: Scripta materialia. Number 226(2023)
• Publication Date: 2023-03-15
• Subjects: Additive manufacturing -- Nucleation -- Al alloys -- ISRO -- Primary phase; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2022.115212
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The strategy aiming at promoting the precipitation of the primary metastable L12 -Al3 X phase is the most widely used to refine grain size in Al alloys designed for additive manufacturing. It is generally admitted that Al grains nucleate onto the primary L12 -Al3 X precipitates by epitaxy resulting in a cube-cube orientation relationship. Here we report TEM observations showing clusters of precipitates of this primary L12 -Al3 X phase. Using Automated Crystallographic Orientation Mapping in the TEM, we show that such clusters consist of various orientations. Analysis of those clusters reveals that some orientations share common 5-fold rotational symmetry axes suggesting that they have nucleated from an icosahedral template. We conclude that Icosahedral Short Range Order (ISRO) in the liquid can play a role in the nucleation of the primary metastable L12 -Al3 Zr phase through the ISRO-mediated nucleation mechanism. Graphical abstract: Image, graphical abstract