Microstructure Refinement and Property Enhancement of Zn-4Al Biodegradable Alloy via Optimized Friction Stir Processing

The effect of friction stir processing (FSP), as a solid-state material modification technique, was studied on the microstructure, mechanical properties, and corrosion behavior of Zn-4Al biodegradable alloy. The results showed that applying FSP under the optimized condition (25 mm/min and 900 rpm) significantly enhanced the mechanical properties where compared to the as-cast Zn-4Al alloy, the hardness, ultimate tensile strength (UTS), and fracture strain were improved by about 45%, 30%, 310%, respectively. Applying FSP also enhanced the corrosion behavior where compared to the as-cast condition the average corrosion current and corrosion rate were decreased from 9.63×10 −6 A/mm 1 to 1.38×10 −6 A/mm 1 and from 0.031 mm/year to 0.025 mm/year, respectively.