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 BC at 579 K. 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 °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.

Microstructural characteristics, mechanical and corrosion properties of a low-alloyed Mg alloy after different deformation processing

“…Figure 3 shows the microstructure of the as ECAPed samples after the first, fourth and fifth passes via route Bc in the cross sections perpendicular to extrusion direction. Generally, by applying ECAP and increasing the number of ECAP passes, dislocation density increases as well which highten the energy of system [18]. When the dislocation density is high enoughinside the grains, they will rearrange to form low angle grain boundaries, by further deformation high angle grain boundaries (HAGB) form.…”

A Multifunctional Flexible Ferroelectric Transistor Sensor for Electronic Skin

“…Therefore, E‐skin equipped with proximity sensing function is expected to be used in artificial intelligence, [ 9 ] human–machine interaction, [ 1 ] and robotics. [ 2 ] Theoretically, proximity sensing can be realized based on any long‐range interactions, including magnetic, [ 5b ] optical, [ 9,38 ] ultrasound, [ 39 ] and electrostatic [ 17 ] interactions. In recent years, FET proximity sensors are reported by using organic [ 25,40 ] and oxide semiconductors [ 17b ] as active layers.…”

PEO of AZ31 Mg Alloy: Effect of Electrolyte Phosphate Content and Current Density

“…The applied electric field can segregate positive and negative ions to create charged regions. During the PEO coating creation, OHand PO [3][4] ions are consumed for the Mg, Mg(OH) 2 and Mg 3 (PO 4 ) 2 creation (see Equations (2)-( 4)). The electrical equilibrium disappeared, causing the movement of OHand PO [3][4] ions from the diffusion part of the electrolyte to the vicinity of the metal surface.…”

“…During the PEO coating creation, OHand PO [3][4] ions are consumed for the Mg, Mg(OH) 2 and Mg 3 (PO 4 ) 2 creation (see Equations (2)-( 4)). The electrical equilibrium disappeared, causing the movement of OHand PO [3][4] ions from the diffusion part of the electrolyte to the vicinity of the metal surface. The resulting rate of ions movement from the diffusive part of the electrolyte is mainly dependent on the permittivity and conductivity of the electrolyte [59,60].…”