渗碳体的结构和一次渗碳体形态的研究

对钢铁中的基本相渗碳体的晶格结构作了进一步的描述:一个碳原子位于由6个铁原子组成的三棱柱体中,每个铁原子为2个三棱柱体所共有;每个渗碳体晶胞含4个这种上下分层、反向、错位排列的三棱柱体,相应的化学计量比为12:4(即3:1)。应用计算机可以形象地揭示渗碳体的结构。根据成分过冷原理对从过共晶铸铁液相中结晶出树枝状一次渗碳体进行了分析。

Structure of Cementite and Morphology of Primary Cementite

The crystalline structure of cementite as a basic phase in steel and cast iron was further described as follows： （a）One carbon atom is located in a triangular prism composed of six iron atoms and each iron atom belongs to two triangular prisms. （b） One cementite cell consists of four triangular prisms that arrange in the form of layerby-layer, opposite direction and stagger order so the stoichiometric ratio is 12：4 （i. e. 3：1 ）. The structure eementite can be graphically revealed with the help of computer. The primary cementite is crystallized from melted hypereuteetie cast iron in dendritic form, which is analyzed in the light of the principle of constituent supercooling.