Metal injection moulding of in-situ formed AlN hollow sphere reinforced Al matrix syntactic foam parts

In-situ formed AlN hollow sphere reinforced Al matrix syntactic foam parts have been fabricated by metal injection moulding, partial nitridation and a subsequent “open-closed pore transformation” without using pre-fabricated ceramic hollow spheres. The in-situ Al matrix systactic foams feature highly controllable pore size of <20 μm and exhibit high strength of ∼200 MPa, which is superior to conventional Al matrix syntactic foams having pre-fabricated ceramic hollow sphere reinforcements.

► First report of in-situ formed metal matrix syntactic foams.
► Ceramic hollow spheres directly synthesized in the matrix through chemical reactions.
► Micron-sized ceramic hollow spheres uniformly distributed in the metal matrix.
► Superior mechanical properties over traditional metal matrix syntactic foams.