High strength SiCp/AZ91 composite assisted by dynamic precipitated Mg17Al12 phase

The 5 mu m10 vol % SiCp/AZ91 composite was extruded successfully at 250 degrees C by the slow speed extrusion (0.01, 0.1 and 1 mm/s). Results indicated that the composite with the yield strength of similar to 371.5 MPa and ultimate tensile strength of similar to 443.9 MPa exhibited much higher tensile strength than present particle reinforced magnesium matrix composites (PMMCs). Such high tensile strength in present work might be attributed to ultra-fine grains and submicron sized Mg17Al12 phases precipitated during extrusion. As the extrusion speed increased from 0.01 to 1 mm/s, both the average size of grains and Mg17Al12 phase increased, while volume fraction of Mg17Al12 phase decreased. All these led to the decrease of yield strength and ultimate tensile strength, however, accompanied by the increase of elongation. (C) 2017 Elsevier B.V. All rights reserved.