Microstructures and mechanical properties of quasicrystal reinforced Mg matrix composites

Mg-based composites reinforced with stable in situ icosahedral quasicrystal phase (I-phase) were fabricated in this Study. The effects of Y content on the microstructures and mechanical properties of the composites were investigated. The results Show that the composites comprised dendrites of alpha-Mg matrix separated by interdendritic I-phase and lamellar (I-phase + alpha-Mg) eutectic. With the increase of Y content, the content of I-phase increases; the content and size of (I-phase + alpha-Mg) eutectic cell increase; the lamellar space between I-phase and alpha-Mg in eutectic cell also increases but the grain size of alpha-Mg matrix decreases. The failure mode of M-Zn-Y alloy matrix composites in tensile tests is quasi-cleavage fracture. With the increase of Y content, the tensile strengths of the composites increase, and (he elongation rates increase firstly and then decrease. (C) 2007 Elsevier B.V. All rights reserved.