Microstructure, Mechanical Properties and Tribological Behavior of Two-Phase Mg-Y-Cu Alloys with Long Period Stacking Ordered Phases

This study is undertaken to investigate the microstructure, mechanical properties and tribological behavior of as-cast Mg100-3xY2xCux(at%,x = 0.5, 1, 1.5 and 2) alloys. The results show that all the alloys had a two-phase structure consisting of alpha-Mg matrix and 18R long period stacking ordered phase. With increasing Y and Cu contents, the average grain size of primary alpha-Mg gradually decreased from 1280 to 146 mu m, meanwhile, the volume fraction of long period stacking ordered phase rapidly increased from 11.8 to 56.4%. As Y and Cu contents increased, the tensile strength and hardness of as-cast alloys were gradually enhanced. The yield strength, ultimate tensile strength and hardness of the Mg(94)Y(4)Cu(2)alloy were 188 MPa, 252 MPa and 86.7 HB respectively, which were increased by 144.2%, 78.7% and 20.2% compared with the Mg(98.5)Y(1)Cu(0.5)alloy. The friction coefficient and the wear rate of as-cast alloys decreased firstly and then increased as Y and Cu contents increased. The Mg(95.5)Y(3)Cu(1.5)alloy exhibited the lowest friction coefficient and the best wear resistance. Graphic

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The study investigated the microstructure, mechanical properties, and tribological behavior of as-cast Mg-Y-Cu alloys. Results showed that increasing Y and Cu contents improved the tensile strength and hardness, while the friction coefficient and wear rate varied with the alloy compositions. Mg(95.5)Y(3)Cu(1.5) alloy exhibited the lowest friction coefficient and the best wear resistance.