铸铁熔体中石墨生长方式的转变与变质机理的探讨

采用液淬技术,对铸铁熔体中石墨生长方式的转变进行了研究,提出了螺旋台阶增殖的概念并给出了两个基本模型。指出:螺旋台阶的增殖是石墨晶体生长方式转变的实质,变质元素Ce能促使石墨由片状转变为球状,初步揭示了石墨的各种结晶形貌形成的原因。

GROWTH MODE AND MODIFICATION OF GRAPHITE IN CAST IRON MELT

Using liquid quenching technique, the change of growth mode of graphite in cast iron melt was analysed. Based on the interface structure theory of crystal growth, the concept of multiplication of spiral growth steps was advanced and two basic multiplication models were given out. It was proposed that multiplication of spiral steps is responsible for the changeof growth mode of graphite in cast iron melt. The modifying elements such as cerium promote multiplication of spiral steps, which is regarded as the core of modification. Origination of screw dislocation and branch of the sector blocks in radius direction, both of which are essential to spheroidization of graphite in the melt, are caused by multiplication of spiral steps; and so is thickening of graphite plates.