2024系列铝合金粗大夹杂相的微观结构研究

MICROSTRUCTURE STUDY OF CONSTITUENT PHASES IN 2024 SERIES Al ALLOYS

本文利用X射线能谱分析、会聚束电子衍射和常规电子衍射对2024系列铝合金粗大夹杂相的结构类型和成分进行了研究。所有夹杂相的合金元素均部分地被其它元素所取代,使粗大夹杂相的成分稍偏离于理想的三元化合物。粗大夹杂相中含量最多的是体心立方α-Al_(12)(FeMn)_3Si,空间群为Im 3,点阵常数α=1.25nm;其次是Cu_2FeAl_7,空间群为P4/mnc,点阵常数α=0.6336nm,c=1.487nm;还有少量的属简单立方的α-Al_(12)Fe_3Si,空间群为Pm 3,点阵常数α=1.27nm。

X-ray microanalysis, convergent beam electron diffraction (CBED) andselected area electron diffraction (SADP) studies have conducted on the structuresand compositions of the constituent phases in 2024 series Al alloys. Partial substi-tution of alloying elements has found to occur in all the constituent phases caus-ing small deviations from the stoichiometric compositions reported for the ternarycompounds. The dominant phase is α-Al_(12)(FeMn)_3Si which has body center cubiccrystal structure, with the Im3 space group and lattice rarameter of α=1.25 nm.The next dominant phase is Cu_2FeAl_7 which has primitive tetragonal crystal struc-ture, with the P4/mnc space group and lattice parameters of α=0.6336nm, c=1.487nm. The minor phase is α'-Al_(12)Fe_3Si which has primitive cubic crystal structure,with the Pm3 space group and lattice parameter of α=1.27 nm.