Development of Magnesium Matrix Syntactic Foams Processed through Powder Metallurgy Techniques
The presence of Hollow particles instead of gas porosity provides a closed cell structure called Syntactic foams. Syntactic foams have gained significant attention in recent years due to their low density, moisture absorption and thermal expansion coefficient compared to other cellular materials, such as open and closed cell structured foams. In terms of mechanical behavior, it is generally more insightful to compare metal matrix syntactic foams with metal foams and metal matrix composites. In comparison with metal foams, they have high compressive yield strength and more homogenous mechanical properties but usually higher densities and lower plasticity. In comparison with metal matrix composites, they have lower strength but offer compressibility, which is not existence in metal matrix composites. Syntactic foams have been extensively studied for aluminum based metal matricesand polymer matrices. Importance in magnesium foams is increasing in recent periods due to their very low density. Only a few studies are available on magnesium matrix syntactic foams processed through powder metallurgy techniques. This review presents an overview of hollow particle filled magnesium matrix (AZ91D/microballons) syntactic foams using powder metallurgy methods.