Effect of hot extrusion on the microstructure and mechanical properties of SiCNWs/Mg-2Zn-0.1Y composite

This work investigates the effect of adding SiC nanowires (SiCNWs) on the microstructure and mechanical properties of Mg-2Zn-0.1Y matrix composites under different hot extrusion parameters, and the strengthening mechanism was analyzed. The results showed that as the extrusion temperature elevated from 140 degrees C to 220 degrees C or the extrusion speed increased from 0.1 mm/s to 1.0 mm/s, both the dynamic recrystallized grain size and the recrystallized volume fraction increased significantly. The changes of precipitate size and volume fraction exhibited the same trend. The finest recrystallized grains (similar to 0.37 mu m) were obtained after extrusion at 140 degrees C and 0.1 mm/s, which also contained nano-sized MgZn2 precipitates and SiC nanowires. As the extrusion temperature increased from 140 degrees C to 220 degrees C at a constant extrusion speed of 0.1 mm/s, the strength of the composites decreased while the elongation improved greatly. Similar change in the strength and elongation were obtained in the composite as the extrusion speed increased from 0.1 mm/s to 1.0 mm/s at extrusion temperature of 140 degrees C. Meanwhile, these composites exhibited a weakened texture, and a mixture of microcracks and dimples was observed in the fracture surfaces of the as-extruded composites, which explained the mix of brittle-ductile fractures of the composites. The composites extruded at 140 degrees C and 0.1 mm/s exhibited the best performance with yield strength (YS) and ultimate tensile strength (UTS) of similar to 495.53 MPa and similar to 514.18 MPa, respectively. Among all strengthening mechanisms, the proportion of grain refinement strengthening is the highest.

Automated summary

The addition of SiC nanowires affected the microstructure and mechanical properties of Mg-2Zn-0.1Y matrix composites under different hot extrusion parameters. Stengthening mechanism was analyzed and the results showed significant changes in grain size and volume fraction with variations in extrusion temperature and speed.