Foaming Mg Alloy and Composite Using MgCO3 Blowing Agent

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Process metallurgy and materials processing science, 2021-04, Vol.52 (2), p.931-943
• Main Authors: Bhosale, Dipak, Devikar, Akshay, Sasikumar, S., Vinod Kumar, G. S.
• Format: Article
• Language: English
• Subjects: Aluminum; Blowing agents; Characterization and Evaluation of Materials; Chemistry and Materials Science; Decomposition; Foamed metals; Foaming; Liquid metals; Liquidus; Magnesium base alloys; Magnesium carbonate; Materials Science; Metallic Materials; Nanotechnology; Original Research Article; Particle size distribution; Particulate composites; Reagents; Stabilizers (agents); Structural Materials; Surfaces and Interfaces; Temperature; Thin Films
• ISSN: 1073-5615; 1543-1916
• DOI: 10.1007/s11663-021-02066-0

The present work reports on foaming of magnesium alloys and composites using MgCO 3 as the blowing agent. Foaming was done via the molten metal route by direct addition of MgCO 3 in molten Mg. The alloys and composites required for foaming were prepared by varying the concentration of aluminum (10 to 30 wt pct) and calcium (0 and 2 wt pct) in Mg. SiC of 10- µ m size and about 10 to 20 vol pct was added as reinforcement particles in the composite. The liquidus temperature of the alloys and composites, the decomposition behavior of MgCO 3 , and the intrinsic oxides that formed in the melt have a significant effect on the structure of the foams. Mg alloys and composites with 30 wt pct Al showed better foaming behavior with higher expansion, lower density, good cell structure, and uniform cell size distribution due to the smaller difference between their liquidus temperature and the decomposition temperature of MgCO 3 . The addition of 2 wt pct Ca showed a significant effect on foaming, and the MgO and MgAl 2 O 4 (spinel) particles formed in situ in the molten Mg during foaming acted as the stabilizing agents.