Zn-2%Cu包晶合金定向凝固的微观组织

MICROSTRUCTURES OF UNIDIRECTIONALLY SOLIDIFIED Zn-2%Cu PERITECTIC ALLOY

对 Ｚｎ－２％Ｃｕ包晶合金进行了定向凝固实验研究，考察了在不同凝固速度条件下获得的凝固组织，并对其组织构成及尺度分布进行了分析 结果表明，组织从低速到高速经历了棒状胞晶—等轴晶—列状胞晶—板状胞晶—共生结构的转变，其中高速组织特征间距λ与凝固速度ｕ之间存在λ·ｖ０．５４７７＝５５０．５的关系，与低速胞晶组织相比较有显著差异；同时在没有出现平界面生长的条件下获得了包晶共生生长组织，由此对包晶共生生长的平界面假设提出了质疑。

Microstructure of unidirectionally solidified Zn-2%Cu (mass fraction) peritectic alloy was investigated, and the coupled growth was achieved at high growth rate. Transition of cellular/equiaxied structure/arrayed cellular/plate-like cellular/coupled growth structure was presented with increasing the growth rate. It is also demonstrated that the characteristic spacing of high growth rate structures satisfies the equation of λ ·v0.5477=550.5, which shows a remarkable difference from that of low growth rate structures.