A new phase MgYZn4 in Mg-Zn-Y alloy was studied using aberration-corrected scanning-transmission electron microscopy and first-principles calculations. Nanometer-sized MgYZn4 precipitates were formed through ordered s...A new phase MgYZn4 in Mg-Zn-Y alloy was studied using aberration-corrected scanning-transmission electron microscopy and first-principles calculations. Nanometer-sized MgYZn4 precipitates were formed through ordered substitutions of Y with 50% Mg atoms in MgZn2. MgYZn4 has an orthorhombic structure with a space group of Pmnn, and lattice parameters a =5.2965∧, b =9.4886∧, and c =8.5966 ∧. Importantly, both size and structure of MgYZn4 are stable at 625 K for 5 h, showing higher thermostability than MgZn2, which should be important for applications at elevated temperatures. The enhanced thermostability of MgYZn4 is attributed to the lower formation energy and bonding enhancement due to Y substitution.展开更多
基金supported by the National Natural Science Foundation of China (Nos.51390473, 51371178, 51771202)the Key Research Program of Frontier Sciences, CAS (No. QYZDY-SSWJSC027)
文摘A new phase MgYZn4 in Mg-Zn-Y alloy was studied using aberration-corrected scanning-transmission electron microscopy and first-principles calculations. Nanometer-sized MgYZn4 precipitates were formed through ordered substitutions of Y with 50% Mg atoms in MgZn2. MgYZn4 has an orthorhombic structure with a space group of Pmnn, and lattice parameters a =5.2965∧, b =9.4886∧, and c =8.5966 ∧. Importantly, both size and structure of MgYZn4 are stable at 625 K for 5 h, showing higher thermostability than MgZn2, which should be important for applications at elevated temperatures. The enhanced thermostability of MgYZn4 is attributed to the lower formation energy and bonding enhancement due to Y substitution.
