摘要
It was recently known that the compositions of industrial alloy specifications generally satisfy simple composition formulas issued from short-range-order structural units in their basic solid solutions. In present work, Cu-Ni face-centered-cubic alloys were further addressed by introducing the cluster-plusglue-atom model for the short-range-order structural descriptions. Composition formulas covering only the first twelve and the second six neighbor shells in the face-centered-cubic lattice are proposed, [Cu-Cu12](Cu,Ni)6 for the Cu-rich alloys and [NiNi12]Cu6 ~ [Ni-Ni12](Cu5Ni) for Monel alloy, the only Ni-rich alloy specficiation, where the square-bracketed part represents a cuboctahedral cluster. The alloy specification selection is also discussed in terms of valence electron numbers per unit formula. The present work confirms that well-established industrial alloys have simple composition rules that reflect the intrinsic short-range-order local structures in the solid solutions.
工业合金牌号成分一般满足简单的成分式,我们认为该成分式源自其固溶体中的化学近程有序.本文通过引入用于描述近程有序结构的团簇与连接原子模型,进一步详细阐述面心立方结构Cu-Ni合金的工业牌号成分解析.我们提出的团簇成分式只涉及第一近邻的十二配位立方八面体团簇(方括号部分)和第二近邻的八面体(连接原子部分),理想满足元素间相互作用:富铜端的白铜对应于[Cu-Cu12](Cu,Ni)6团簇式,在富镍端只有蒙乃尔一种工业牌号合金,用团簇式[Ni-Ni12]Cu6~[Ni-Ni12](Cu5Ni)来解析.我们还指出,团簇式对应着特定的价电子总数规律.本工作进一步证实,工业合金牌号背后隐藏着体现固溶体近程有序本质的成分规律.
基金
supported by the National Natural Science Foundation of China(NSFC)(11174044)
the Grade A Natural Science Research Project of Fujian Province Education Department(JA12306)
