单斜η-Al_(11)Cr_2相的确定

Crystallographic characterization of the monoclinic η-Al_(11)Cr_2

本文用高温快冷的方法得到了Al-Cr二元合金系中η-Al11Cr2相的单晶,综合单晶X射线衍射、选区电子衍射以及高分辨电子显微像等研究方法确认η-Al11Cr2为单斜相,a=1.77348(10)nm,b=3.04555(17)nm,c=1.77344(10)nm,β=91.0520(12)°,空间群为C2/c。通过对名义成分为Al11Cr2的铸锭在不同温度下进行退火处理后的金相分析,首次观察到了包晶反应μ-Al4Cr+Lη-Al11Cr2,且证实了共析反应η-Al11Cr2-μAl4Cr+-θAl7Cr的存在。

In this paper, crystals of η-Al11Cr2 were found in the holes of ingots, confirming the existence of this phase. By combining the experimental results of single-crystal X-ray diffraction and selected area electron diffraction, the crystallographic parameters were obtained as a = 1.77348（10） nm, b = 3.04555（17） nm, c = 1.77344（10） nm, monoclinic angle β = 91.0520（ 12）°and space group C2/c is confirmed. Through observation of SEM phase mierographs of specimen heat-treated at different conditions, the peritectic reaction η-Al11Cr2 ＋ L（liquid phase）←→η-Al11Cr2 was observed and the euteetoid decomposition of the η-Al11Cr2 phase （η-Al11Cr2←→μ-Al4Cr＋θ-Al1Cr） was confirmed.