Effect of ECAP Processing on Corrosion Behavior and Mechanical Properties of the ZFW MP Magnesium Alloy as a Biodegradable Implant Material
Abstract
Equal channel angular pressing (ECAP) is used to investigate the influence of microstructural evolution on mechanical properties and corrosion resistance of an extruded Mg alloy (ZFW MP) via route B-C at 579K. The transmission electron microscope (TEM) and the optical microscope (OM) are used to observe the microstructure.
Tensile testing and hardness measurement are used to investigate the mechanical properties at room temperature, and electrochemical impedance spectroscopy (EIS) and potentiodynamic measurements are used to examine the corrosion properties in Hank's solution at 37 degrees C. The ECAPed samples show the enhanced mechanical properties as compared with the extruded sample.
The ECAPed ZFW MP alloy possesses a homogeneous microstructure due to dynamic recrystallization (DRX), as indicated by the resulting microstructures. However, the electrochemical measurements show that a reduction in the corrosion resistance is caused by the ECAP processing.
A broader grain size distribution and a continuous network of the oxide layers along grain boundaries result in an improvement in the corrosion resistance in the extruded sample as compared with the ECAPed sample. However, better mechanical properties are observed with a further homogeneous microstructure in the ECAPed sample as compared with the extruded counterpart.