Fe-1.18Cu合金过饱和固溶体中的纳米条带结构

Nanometer fringe structure in super saturated solid solution of Fe-1.18Cu alloy

研究铜在钢中的沉淀规律具有重要意义.应用JEM-2010高分辨电镜研究了Fe-1.18Cu合金过饱和固溶体的组织结构.发现该合金固溶处理后并没有得到均匀的含铜的固溶体,而是在铁素体晶粒中分布着大量的铜原子的偏聚区,呈圆饼状,直径约10～30 nm.偏聚区与铁素体基体间没有清晰的界面,每个偏聚区由5～9片类似孪晶的衍射条纹构成.各衍射条纹中的（110）α晶面存在位向差,因此呈现明暗相间的衬度.铜原子主要偏聚在铁素体的{001｝}α上.将这种衍射条纹命名为纳米条带结构,并对其成因进行了探讨.

Study on the law of solution and precipitation of copper is significant. The microstructure of super saturated solid solution in Fe-1.18Cu alloy was investigated under JEOL JEM-2010 transmission electron micrescope（TEM）. The results indicated that the solution state was heterogeneous super saturated solid solution, lots of Cu atom clusters took the shape of a cake and distributed in fertile matrix instead. There are not evident interfaces between clusters and ferrite matrix. There are five to nine diffractive stripes which resemble the twin etystal in every cluster. There is 2°-4° orientation deviation between every two （001）α-Fe planes stripes, therefore, presenting the contrast which the light and shade alternates with. Cu atoms were clustered on the {001} α-Fe planes. These diffractive stripes are named as the nanometer fringe structure. Moreover, the formation mechanism of nanometer fringe structure appearance was discussed.