The role of solute in grain refinement of magnesium

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 31; no. 11; pp. 2895 - 2906
• Main Authors: LEE, Y. C, DAHLE, A. K, STJOHN, D. H
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01-11-2000; Springer Nature B.V
• Subjects: Alloying; Aluminum; Applied sciences; Calcium; Exact sciences and technology; Grain refinement; Grain size; Magnesium alloys; Magnesium base alloys; Metals. Metallurgy; Production of alloys; Production of metals; Production of non ferrous metals. Process materials; Silicon; Solidification; Strontium; Supercooling; Zirconium; Grain size; Superheating; Grain refining; Alloying effects; Calcium addition; Silicon addition; Solutes; Aluminium addition; Magnesium; Experimental study; Strontium addition; Zirconium addition
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/bf02830349

The effect of separate solute additions of Al, Zr, Sr, Si, and Ca on grain size of Mg has been investigated. Increasing the Al content in hypoeutectic Mg-Al alloys resulted in a continuous reduction in grain size up to 5 wt pct Al, reaching a relatively constant grain size for higher Al contents (above 5 wt pct). The effect of Sr additions was investigated in both low- and high-Al content magnesium alloys, and it was found that Sr had a significant grain refining effect in low-Al containing alloys but a negligible effect on grain size in Mg-9Al. Additions of Zr, Si, and Ca to pure magnesium resulted in efficient grain refinement. The grain refinement is mainly caused by their growth restriction effects, i.e., constitutional undercooling, during solidification, but the effect of nucleant particles, either introduced with the alloying additions or as secondary phases formed as a result of these additions, may enhance the grain refinement. A brief review of grain refinement of magnesium alloys is included in this article to provide an update on research in this field.