Effects of rare earth yttrium on microstructure and properties of Mg-Al-Zn alloy

The effects of rare earth yttrium (Y) addition on the microstructure, mechanical properties and corrosion behavior of degradable Mg-15Al-5Zn-xY (x = 0, 0.15, 0.25, 0.5, 3, 5. mass. fraction) alloys were investigated using X-ray diffraction, scanning electron microscope, electron microprobe analysis, transmission electron microscopy, Vickers hardness, compression properties, immersion tests and electrochemical measurements. The results show that the main phases in the alloys with rare earth yttrium element consist of alpha-Mg, beta-Mg17All2, phi-Al5Mg11Zn4 and Al2Y. When the content of yttrium element is 0.25 mass.%, the hardness of the alloy reaches 119 HV, with the compressive strength up to 417 MPa. In addition, the morphology of the beta phases changed and Al2Y phases with face-centered cubic (FCC) structure formed in the alpha-Mg, which greatly improves the corrosion resistance properties of the alloy. The corrosion rate reaches a maximum of 7.0 x 10(-3) mm/day at room temperature and 0.111 mm/day at 93 degrees C. (c) 2018 Elsevier B.V. All rights reserved.