Pb-30%Bi包晶合金定向凝固的两相微观组织研究  

Investigation of Two-Phase Microstructure During Directional Solidification of Pb-30wt%Bi Peritectic Alloy

作　　者：胡小武[1] 李双明[1] 高斯峰[1] 刘林[1] 傅恒志[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《铸造》2010年第5期445-449,共5页Foundry

基　　金：国家自然科学基金资助项目(50395100;50971101);新世纪优秀人才基金(07-0692;34-TP-2009)

摘　　要：对Pb-30%Bi包晶合金进行定向凝固试验,研究了在不同生长速率、不同试样直径条件下获得的两相微观组织,并对其组织的形成及微观组织尺度进行分析。试验结果表明,当生长速率V由1μm/s逐渐增大到100μm/s时,微观组织经历胞状初生α相+胞间包晶β相到枝晶状α相+枝晶间β相微观组织的转变。当生长速率V≤0.5μm/s时,在小直径(1.8 mm)试样中发现不完全带状组织,而在大直径(7 mm)试样中却得到了振荡组织。同时发现,初生α相的一次枝晶间距λ与凝固速率V之间存在λV0.16=241.0μm1.16s-0.16的关系,这与Hunt模型和Trivedi模型较好地吻合。Directional solidification experiments were conducted on Pb-30 wt%Bi peritectic alloy to investigate the two-phase microstructure at various growth rates and diameters of samples, and the formation of two-phase microstructure and the micro-scale were also studied. The experiment results show that the transition of the structure from cellular primary a phase and inter-cellular peritectic β phase to dendritic primary a phase and inter-dendritic peritectic β phase was presented with increasing the grOwth velocity from 1 μm/s to 100 μm/s. Whereas the incomplete banded structure and the oscillatory structure were observed in sample with diameter of 1.8 mm and 7 mm as the growth rate V≤0.5 μm/s, respectively. It is also demonstrated that the primary dendrite arm spacing of a phase coincides with the equation of λV^0.16=-241.0μm^1.16s^0-0.16, which shows a good agreement with Hunt model and Trivedi model.

关 键 词：Pb-30%Bi包晶合金 微观组织演化 定向凝固 一次枝晶间距 

分 类 号：TG111.4[金属学及工艺—物理冶金]