Phase equilibria and crystal structure of ternary compounds in Al-rich corner of Al-Er-Y system at 673 and 873 K

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2021,（1）
• 页码范围: 128-138
• 页数: 11页
• 语种: 英文

摘要

Phase equilibria in the Al-rich corner of the Al-Er-Y ternary system from 65 at.％to 100 at.％Al at 673 and 873 K were investigated, and the two isothermal sections were established by X-ray diffraction (XRD), scanning electron microscope (SEM) and electron probe micro analysis (EPMA). Three ternary-phase regions are observed and the phase relations are similar at both isothermal sections. There are two ternary compounds, and a complete crystal structures and composition ranges of the two ternary compounds are determined asτ 1 (Al75-76Er15-22Y2-10, R-3m) andτ 2 (Al75-76Er11-17Y7-14, P63/mmc) via XRD, focused ion beam coupled with transmission electron microscope (FIB-TEM) and EPMA. Meanwhile, the solubilities of the third element in the binary compounds at both temperatures are measured. The solubility of Er inβ-Al3Y phase reaches to 6.6 at.％and that of Y in Al3Er phase reaches to 1.5 at.％after annealing at 873 K. The temperature effect is not obvious for the phase equilibria at 673 and 873 K, but it increases the solubility of Er inβ-Al3Y, while it is not obvious for both the solubility of Y in Al3Er and that of Er and Y in (Al). The phase equilibria of the Al-Er-Y ternary system determined by the present work have provided new phase diagram data for a future thermodynamic assessment of this system.