Solidification Processing of Magnesium Based In-Situ Metal Matrix Composites by Precursor Approach

In-situ magnesium based metal matrix composites (MMCs) belong to the category of advanced light weight metallic composites by which ceramic dispersoids are produced by a chemical reaction within the metal matrix itself. In-situ MMCs comprised uniform distribution of thermodynamically stable ceramic dispersoids, clean and unoxidized ceramic-metal interfaces having high interfacial strength. In last two decades, investigators have been collaborating to explore the possibility of enhancing the high temperature creep resistance performance in polymer-derived metal matrix composites (P-MMCs) by utilizing polymer precursor approach. A unique feature of the P-MMC process is that since all constituents of the ceramic phase are built into the polymer molecules itself, there is no need for a separate chemical reaction between the host metal and polymer precursor in order to form in-situ ceramic particles within the molten metal. Among the different polymer precursors commercially available in the market, the silicon-based polymers convert into the ceramic phase in the temperature range of 800–1000°C. Therefore, these Si-based polymers can be infused into molten Mg or Mg-alloys easily by simple stir-casting method. This chapter mainly focuses on understanding the structure–property correlation in both the Mg-based and Mg-alloy based in-situ P-MMCs fabricated by solidification processing via polymer precursor approach.

Ultrasonication Assisted Fabrication of Aluminum and Magnesium Matrix Nanocomposites - A Review

Recent researches in the domain of casting confirmed that the mechanical properties of aluminum and magnesium based nanocomposites can be appreciably enhanced when ultrasonic cavitation assisted solidification processing is used. Ultrasonic cavitation assisted solidification processing is used for the manufacturing of aluminum and magnesium alloy based metal matrix nanocomposites reinforced with nanoceramic particles. In this solidification processing, formation of clusters have been minimized and the nanoreinforcements were distributed uniformly in aluminum and magnesium matrix nanocomposites. The ultrasonic assisted casting approach will manage the grain dimensions via minimizing agglomeration of nanoparticles in metal matrices. This paper opinions the properties and morphology of aluminum and magnesium based metal matrix nanocomposites fabricated through ultrasonic assisted casting process.

Titanium Nitride and Niobium Carbide in the Ferritic Stainless Steel and the Influence to Casting Macrostructure

Titanium and niobium were applied to stable the carbon or nitrogen which dissolved ferritic stainless steel for improving the anti-corrosion performance. The titanium nitride and niobium carbide had been formed during solidification processing. For understanding those precipitates how to influence the casting macrostructure, three steels that had different content of niobium and the fixed content of titanium had been designed. The result showed the casting macrostructure of ingot and the grain size of the centre-equiaxed crystal zones had different tendency. And the titanium nitride and niobium carbide had interacted.