Mechanical characteristics and in vitro degradation of biodegradable Zn-Al alloy

Abstract

Zn-5wt.%Al alloy was cast and extruded into the tube in the present work. The mechanical properties and degradation behavior of as-cast and extruded alloys were investigated. Compared with other binary Zn alloys, the extruded Zn-5wt.%Al alloy tube showed a ultra-high elongation to failure (383.3%) and medium strength (257 MPa). The superplasticity is attributed to the grain boundary slip due to unique microstructure, i.e. the ultrafine-grained α-phase accumulated mainly along the fine-grained η-phase boundary. Furthermore, after 32 days’ immersion, the corrosion rates of as-cast and extruded alloy were 0.11 mm/y and 0.15 mm/y, respectively. The electrochemical polarization test and corrosion surface analysis indicate an initial ultrafine-grained Al-rich phase dissolution for extruded Zn-5wt.%Al alloy.