Abstract

This study is undertaken to investigate the microstructure, mechanical properties and tribological behavior of as-cast Mg_100−3xY_2xCu_x (at%, x = 0.5, 1, 1.5 and 2) alloys. The results show that all the alloys had a two-phase structure consisting of α-Mg matrix and 18R long period stacking ordered phase. With increasing Y and Cu contents, the average grain size of primary α-Mg gradually decreased from 1280 to 146 μm, 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 Mg₉₄Y₄Cu₂ 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_98.5Y₁Cu_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_95.5Y₃Cu_1.5 alloy exhibited the lowest friction coefficient and the best wear resistance.

Graphic Abstract

中文翻译：

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长周期堆积有序相两相Mg-Y-Cu合金的显微组织、力学性能和摩擦学行为

摘要

本研究旨在调查铸态 Mg _{100−3 x} Y _{2 x} Cu _x (at%, x  = 0.5, 1, 1.5 and 2) 合金的微观结构、机械性能和摩擦学行为。结果表明，所有合金均具有由α-Mg基体和18R长周期堆积有序相组成的两相结构。随着Y和Cu含量的增加，初生α-Mg的平均晶粒尺寸从1280 μm逐渐减小到146 μm，同时长周期堆积有序相的体积分数从11.8%迅速增加到56.4%。随着Y和Cu含量的增加，铸态合金的抗拉强度和硬度逐渐增强。镁合金的屈服强度、极限抗拉强度和硬度₉₄ Y ₄ Cu ₂合金分别为188 MPa、252 MPa和86.7 HB，比Mg _98.5 Y ₁ Cu _0.5合金提高了144.2%、78.7%和20.2% 。随着Y和Cu含量的增加，铸态合金的摩擦系数和磨损率先降低后增加。Mg _95.5 Y ₃ Cu _1.5合金表现出最低的摩擦系数和最好的耐磨性。

图形摘要