Microstructure and compressive properties of solution heat-treated magnesium-Mg2Si in-situ composite foams after complex modification

Abstract

In this study, open-cell Mg composite foams reinforced with in-situ Mg2Si were prepared. In order to refine the Mg2Si compound, the composite foams were co-modified with Y + Sb elements followed by solution heat treatment. The influences of complex modification and holding time of solution heat treatment on the microstructure and compressive properties of the composite foams were studied. The experimental results show that the morphology of Mg2Si is effectively changed by complex modification. The coarse dendritic primary Mg2Si (∼40 μm) is altered to the fine polygonal shape (∼10 μm); the coarse eutectic Mg2Si is transformed to a long rod or granular shape. Both compressive strength and energy absorption capacity of the composite foams are significantly increased. Additionally, with the increasing holding time of solution heat treatment, the eutectic Mg2Si undergoes obvious spheroidization, and the corner of the primary Mg2Si occurs passivation. Consequently, the compressive strength and energy absorption capacity are further improved.