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Existing form of Sc in metal-inert gas welded Al-0.60Mg-0.75Si alloy and its role in welding strength.
- Source :
-
Materials Characterization . Mar2023, Vol. 197, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
-
Abstract
- The existing form of Sc in Si-containing 6xxx-series Al alloys and its role in strength has always been controversial. In this study, isothermal section phase diagram of the Al-0.60 wt%Mg-Si-Sc system at 350 °C was calculated by CALPHAD method and Pandat software, and the results show that Sc exists in Al 3 Sc or V (AlSc 2 Si 2) phases, depending on the contents of Si and Sc. Subsequently, we designed a Al-0.60 Mg-0.75Si-0.05Sc (wt%) Melt Inert Gas (MIG) welded alloy, and investigated its microstructure and mechanical property by tensile tests and electron microscopy. HRTEM and STEM-EDS results show that, Sc exists in the form of core(Sc)-shell (Si) structured (Al, Si) 3 Sc transition phases with the size range of 60–80 nm in the fractured zone (heat affected zone, HAZ) of the welded joints, deriving from equilibrium phase diagram, V (AlSc 2 Si 2) theoretically. The HAZ of the Al-Mg-Si-Sc joint consists of partly recrystallized grains and strong rolling texture, different from the completely recrystallized and coarsened grains in the Al-Mg-Si joint. In addition, the (Al, Si) 3 Sc phases increase the density of β'′ aging strengthening phases and prevent them from coarsening under welding heat cycle. The above positive effects of (Al, Si) 3 Sc particles increase the yield strength, ultimate tensile strength and elongation of Al-Mg-Si welded joints by 31 MPa (20.6%), 41 MPa (21.2%) and 0.8% (12.9%), respectively. [Display omitted] • Clarify the existing form of Sc in metal-inert gas welded Al-Mg-Si alloys. • Investigate the thermal stability of (Al, Si) 3 Sc phases and their effects on microstructure under welding thermal cycle. • Quantify the role of Sc in strength of metal-inert gas welded Al-Mg-Si alloys. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10445803
- Volume :
- 197
- Database :
- Academic Search Index
- Journal :
- Materials Characterization
- Publication Type :
- Academic Journal
- Accession number :
- 161956921
- Full Text :
- https://doi.org/10.1016/j.matchar.2023.112649