Effects of Nd on microstructures and properties of extruded Mg–2Zn–0.46Y–xNd alloys for stent application

The microstructures, mechanical and corrosion properties of three extruded Mg–2Zn–0.46Y–xNd alloys (x = 0.0, 0.5, 1.0 wt%) were studied by optical microscopy, scanning electronic microscopy (SEM), electrochemical measurements and tensile tests. Microstructural observations indicated that Nd led to the uniformity and the variation of morphology of major second phase; tensile tests showed that Nd can improve the ductility at moderate amount (0.5 wt%) and will be detrimental up to 1.0%; Mg–2Zn–0.46Y–0.5Nd alloy exhibited excellent mechanical properties (σb, 269.0 MPa, σ0.2, 165.6 MPa and elongation, 24%); electrochemical tests revealed that Nd can enhance the corrosion resistance and Mg–2Zn–0.46Y–1.0Nd alloy had lowest corrosion current density, which was reasoned that the line-shape and rodlike NdZn2 phase might serve as corrosion barriers and the dissolved Nd can raise the electrode potential of the matrix.