Alloy and Composite Generation in a Semisolid State
Although the conventional alloys are formed mainly in a molten phase, the ideas of incomplete melting were attempted in the past. A technique based on particulate precursors with different melting points and described as semisolid forming of elementally blended powders, was applied in the 1970s to the Ti-Al system . Similarly, Al and Al-30%Mg powders were partially melted to create a family of Al—Mg alloys . In contrast to the homogeneous mixing of precursors during complete melting, partial melting selectively distributes alloying elements and phases derived from each precursor between the matrix and the unmelted component. As a result, the properties of created alloys vary in a more complex way than those anticipated from a simple rule of mixtures. The separate control of the chemical composition of a liquid matrix and primary solid phase creates an opportunity for building unique structures required for specific properties. Thus, combining two or more thixotropic slurries would allow the creation of new alloys, essentially different from those obtained after the complete melting of metallic ingredients. The experiments with several magnesium alloys show that the control of chemistry and the proportion of precursors, as well as the solid to liquid ratio during their partial melting, allow the selective partition of alloying elements between the solid and liquid phases, thus designing unique solidification microstructures.
KeywordsMagnesium Alloy Partial Melting Solid Content Metallic Glass Injection Molding
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- 1.Young, RMK, Clyne TW (1986) Jourmal of Materials Science 21:1025Google Scholar
- 4.Mayencourt C, Schaller R (1999) A high damping magnesium matrix to limit fatigue in composite. Journal of Reinforced Plastics and Composites 18(18):1677–1688Google Scholar
- 14.Czerwinski F (2004) The concept and technology of alloy formation during semisolid injection molding. In Magnesium Technologies SP-1947, SAE International, Warrendale, Pa, USA, pp 45–49Google Scholar
- 17.Brooks CR (1982) Heat Treatment, Structure and Properties of Non-ferrous Alloys. ASM International, Metals Park, Ohio, USAGoogle Scholar
- 18.Mortensen A, Cornie JA, Flemings MC (1988) Solidification processing of metal-matrix composites. Journal of Metals 12 Feb. 1988Google Scholar