Interface microstructure evolution and mechanical properties of the extruded fiber-reinforced aluminum-based composite bar

Abstract

In this work, an extrusion die for inserting the continuous wire rope into the aluminum alloy bar is designed and manufactured, then the extrusion experiments are carried out at 500 °C. The interface microstructure evolution and mechanical properties of the composite bar are studied by different material characterization methods. As the size of micro-voids decreases, the bridging behavior is found. The interface grain boundaries gradually form and migrate, where the evolution of micro-voids from 10 μm to 1 μm is observed. Meanwhile, new grains across the welding interface are formed. Moreover, it is found that the enrichment of Zn and Si and the existence of micro-voids retard the diffusion of Fe and Al on the Fe/Al interface, and the thickness of diffusion layer ranges from 1 μm to 5 μm. Compared with the extruded bar without wire rope, there is a stress drop of 17.6 MPa on the stress-strain curve of the composite bar, but its mechanical properties are not obviously improved due to the worse Fe/Al bonding interface and the brittle FeAl solid solution. Finally, the intergranular fracture mode is illustrated, which is mainly caused by the coarse recrystallized grains with high angle grain boundaries. Keywords: Extrusion, Fiber-reinforced aluminum-based composite bar, Welding behavior, Diffusion behavior, Micro-voids