Microstructure, mechanical properties, and corrosion behavior of degradable Mg-Al-Cu-Zn-Gd alloys.

The effects of Gd addition on microstructure, mechanical properties and corrosion behavior of degradable Mg-17Al-7Cu-3Zn- x Gd ( x = 0, 1, 2, 3. weight fraction) alloys were investigated using optical microscope, scanning electronic microscope equipped with energy dispersive spectroscope, compression tests, electrochemical measurements, and immersion tests. The main phases in the alloys with rare earth Gd consist of α-Mg、β-Mg 17 Al 12 、T (Al 13 Mg 14 Cu 5 Zn 1 ) and (Al,Mg) 3 Gd. The Mg-17Al-7Cu-3Zn-1Gd alloy exhibits the maximum yield strength of 302 MPa, ultimate compression strength of 440 MPa, and degradable corrosion rate of 0.21 mm/day. The significant improvements in compression strength and degradable rate were attributed to the dense network-shaped β-Mg 17 Al 12 phase forming on the grain boundaries of the α-Mg matrix and tubular-shaped T phase. The cuboid-shaped (Al, Mg) 3 Gd phases refine the grain size, and thus improve the mechanical properties and corrosion resistance of the based alloys. [ABSTRACT FROM AUTHOR]