Structure and properties of rapidly solidified Al rich Al-Mn-Si alloys : Part I : Melt spun ribbons

• Published in: Journal of materials science Vol. 34; no. 4; pp. 735 - 747
• Main Authors: WILKES, D. M. J, JONES, H
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 1999; Springer Nature B.V
• Subjects: Aluminum base alloys; Applied sciences; Arrays; Coalescing; Coarsening; Cross-disciplinary physics: materials science; rheology; Evolution; Exact sciences and technology; Hardening; Heat treating; Heat treatment; Icosahedral phase; Manganese; Materials science; Melt spinning; Metals. Metallurgy; Microstructure; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase transitions; Physics; Rapid solidification; Silicon base alloys; Solid solutions; Solidification; Solution strengthening; Spheroidizing; Spheroids; Manganèse alloy; Solid solution strengthening; Heat treatment; Aluminium base alloys; Silicon alloy; Rapid solidification; Rapidly solidified alloy; Melt spinning; Hardness; Microstructure; Hall Petch relationship
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1004516728379

The evolution of microstructure as-spun and during subsequent heat treatment at 200 to 500°C for up to 1000 h has been studied for Al-6.3 Mn-3.3 Si, Al-8.3 Mn-3.7 Si and Al-14.5 Mn-5.8 Si (wt %) alloys, containing 17, 26 and 48 vol % αAlMnSi at equilibrium respectively. Microstructure as-spun ranged from primary icosahedral phase nucleating radial cellular αAl arrays to less regular duplex arrays of αAl and αAlMnSi with decreasing alloy content and decreased section thickness or reduced distance from the chill surface. Heat treatment in the range 200 to 500°C transformed any icosahedral phase present to αAlMnSi along with spheroidization and coarsening/coalescence of αAlMnSi, to produce isolated spheroids when volume fraction f was lower and very stable interlinked chains at higher f. Measured coarsening rates of αAlMnSi were a factor of 10 below predictions of LSW theory at lower f but were within a factor of 2 of prediction at highest f. Hardness was governed by a combination of Hall-Petch and matrix solid solution hardening as-spun supplanted by particle-radius dependent Orowan combined with matrix Hall-Petch hardening for the evolution of hardness during prior long term heat treatment at 425°C.