Structure formation and multistep nucleation in CASTING Al-Mg-Si alloys. (2nd September 2020)

• Record Type: Journal Article
• Authors: Trudonoshyn, Oleksandr; Prach, Olena; Slyudova, Anna; Lisovskii, Vitaliy
• Is Part Of: International journal of cast metals research. Volume 33:Number 4/5(2020)
• Page Start: 184
• Page End: 193
• Publication Date: 2020-09-02
• Subjects: Al-alloys -- heterogeneous nucleation -- multistep nucleation -- nucleating particles -- primary crystals -- spiral eutectic; Metal castings -- Periodicals; Founding -- Periodicals; Foundry research -- Periodicals; Foundry chemistry -- Periodicals; 671.2
• DOI: 10.1080/13640461.2020.1822632
• Languages: English
• ISSNs: 1364-0461

Abstract

ABSTRACT: The process of multistep nucleation during solidification in hypoeutectic Al-Mg-Si casting alloys was investigated. The morphology of the nucleating particles, Mg2 Si primary crystals and Al-Mg2 Si eutectic, was investigated with scanning electron microscopy (SEM) on polished and deep etched microsections. The mechanism of formation of the Mg2 Si crystal was attributed to heterogeneous nucleation on the nucleating particles. It was observed that the majority of the alloys particles found in the studied are oxides. It was established that eutectic Al–Mg2 Si in hypoeutectic alloys has the morphology of 'eutectic crystal', where one face of the crystal has triangular-spiral morphology. The mechanism of formation of Al-Mg2 Si eutectic cells is attributed to epitaxial growth on Mg2 Si crystals. The microhardness of the structural components (Mg2 Si crystals, α-Al dendrites, Al-Mg2 Si eutectic, and Al3 Ti crystals) was measured using Vickers hardness tester.