Evidence that the liquid structure affects the nucleation of the primary metastable L12-Al3Zr in additive manufacturing.
- Resource Type
- Article
- Authors
- Buttard, Maxence; Martin, Guilhem; Harrison, Patrick; Rauch, Edgar F.; Chéhab, Béchir; Jarry, Philippe; Blandin, Jean-Jacques; Donnadieu, Patricia
- Source
- Scripta Materialia. Mar2023, Vol. 226, pN.PAG-N.PAG. 1p.
- Subject
- *NUCLEATION
*ROTATIONAL symmetry
*PRECIPITATION hardening
*ELECTRON beam furnaces
*GRAIN size
*LIQUIDS
*EPITAXY
- Language
- ISSN
- 1359-6462
The strategy aiming at promoting the precipitation of the primary metastable L1 2 -Al 3 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 L1 2 -Al 3 X precipitates by epitaxy resulting in a cube-cube orientation relationship. Here we report TEM observations showing clusters of precipitates of this primary L1 2 -Al 3 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 L1 2 -Al 3 Zr phase through the ISRO-mediated nucleation mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]