Nickel‐Coated Hollow Glass Microspheres Enable Interface Strengthening and Enhanced Energy Absorption in Mg–Al Composite Foams Fabricated by Spark Plasma Sintering

Metal matrix composite foams (MMCFs) hold significant potential for aerospace and automotive applications due to their lightweight nature, high strength, and excellent energy absorption. This study aims to enhance the microstructure and mechanical properties of magnesium–aluminum (Mg–Al) matrix composite foams by incorporating nickel‐coated hollow glass microspheres as fillers, fabricated via spark plasma sintering (SPS). The effects of sintering temperature (380–450 °C) and pressure (10–25 MPa) on the microstructure, interfacial bonding, and mechanical performance are systematically investigated. Results indicate that the nickel coating substantially strengthens the interfacial bonding between the hollow microspheres and the Mg–Al matrix, leading to a more uniform pore structure. Under the optimized sintering conditions of 450 °C and 15 MPa, the compressive strength of the nickel‐coated samples reaches 220.78 MPa, marking a remarkable 56.1% improvement over the uncoated counterparts. The enhancement mechanism is attributed to the promoted elemental diffusion and metallurgical bonding at the interface facilitated by the nickel coating. This work provides valuable theoretical insight and experimental guidance for the design and application of high‐performance Mg–Al based composite foams.