Effect of Rare-Earth Element Y on the Microstructure and Mechanical Properties of the Mg-6.0wt.%Zn-0.5wt.%Zr Alloy

Abstract:

The extruded Mg-6.0wt.%Zn-0.5wt.%Zr (ZK60) alloys with 0.5wt.% and 1.0wt.% Y additions were prepared. The microstructures and tensile properties of the alloys aged in different conditions were investigated. The results show that the specimen with 1.0wt.% Y additions and aged at 453K for 15 h had the best tensile strength. The ultimate tensile strength and yield strength reached 365MPa and 352MPa, respectively. The grain refinement, the formation of the fine dispersed Mg-Zn particles and the W-Mg₃Zn₃Y₂ ternary phase may be the main reasons for the improvement. The average grain size reached to ~ 3μm. The size of the fine and dispersed particles was only several nanometers and the particle number density (Nv) was very high. The crystallographic characteristics of the ternary W-Mg₃Zn₃Y₂ phase were studied by the transmission electron microscope and selected area electron diffraction techniques. The crystallographic orientation relationship between the W phase and the α-Mg matrix is identified as: [2 0]_α//[ ]_w, (0002)_α plane near parallel to the (220)_w plane with a 3.5 degree angle difference. This orientation relationship has rarely been studied and reported.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 91-96
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.91
• Online since: June 2017
• Authors: Yu Liu, Ji Xue Zhou, Yun Teng Liu, Shou Qiu Tang
• Keywords: Crystallographic Orientation, Grain Refinement, Magnesium Alloys, Rare-Earth, Tensile Behavior

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