在GH302合金的萃取μ相电子衍射花样中,(经X射线粉末衍射确定为μ相)出现了μ相空间群为(?)m的-h+k+l(?)3n禁止衍射。例如:[001]带轴中的{100},{200}等衍射斑点,以及{111}带轴中的{(?)},{(?)}等衍射斑点,这些禁止衍射斑点,不属于二次衍射,高级劳厄带或者其它物相(例如MgZn_2型Laves相)的衍射斑点。因此,根据衍射消光规律可以确定该物相为简单六方点阵,其晶胞参数与μ相((?)m)用六方点阵所描述的情况相符合。它可能是一种μ相局部有序结构。
A study was made of the electron diffraction patterns of extracted μ-phase which identified with that of X-ray powder diffraction in superalloy GH302.It is shown that the reflections with—h+k+l≠3n spots, e.g. {100}, {200},etc.in [C01] zone and {110},{101}, etc. in [111] zone (indexed as hexagonal) are forbidden for the R3m space group. These "forbidden" diffractions cannot be attributed to double diffraction with neither non-zero Laue zone nor other phases such as MgZn_2 type Laves phase. Based on diffraction extinction law, it seems to be a primitive hexagonal lattice (P6). Its lattice constant is consistent with that of μ-phase (R3m) described as hexagonal. It may be a kind of local-ordering structure of μ-phase.
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