摘要
采用定向凝固实验方法考察了低凝固速度（下限为０．５ｍｍ／ｈ）下稀土变质铸铁石墨形态的转变。结果表明，随着稀土含量的增加，石墨形态呈现由Ａ型片状→Ａ′型片状→珊瑚状→蠕虫状→球状→开花状的一系列转变；石墨形态由片状到非片状的转变是由于生长方式改变所致，而这种改变取决于稀土含量，与凝固速度（或冷却速度）无关；石墨单体可以发生片状与非片状之间的连续转变，但在试样宏观的片状石墨区域与非片状石墨区域之间却存在着明显的分界线，说明石墨生长方式在试样宏观区域间发生了突变。
The transformation of graphite morphology in rare earth modified cast iron at lower solidification rate (≥0.5 mm/h) has been investigated by unidirectional solidification technique. It is showed that the shape of graphite transforms in sequence of flake type A→flake type A ′→coral→vermicular→spheroidal→explorded form with the increase of rare earth content. The transformation of graphite morphology from flake to no flake form is caused by the variation of growth mechanism determined by rare earth content instead of solidification rate (or cooling rate). This transformation may occur in a single particle of graphite, but there is a clear demarcation between the area of flake graphite and that of no flake graphite, which indicates that the growth pattern of graphite changes suddenly at different areas of specimen.
出处
《钢铁研究学报》
CAS
CSCD
北大核心
1999年第1期41-47,共7页
Journal of Iron and Steel Research
基金
河南省自然科学基金
关键词
定向凝固
铸铁
稀土变质
石墨形态
unidirectional solidification,cast iron,rare earth modification,graphite morphology
