凝固模式对定向凝固多孔铜锰合金气孔结构的影响

摘要

By the directional solidification of metal-gas eutectic method (GASAR), porous Cu-Mn alloy with oriented pores was fabricated successfully. The variation of pore structure was studied by experiments. The results show that the pore structure is primarily dependent on the solidification mode (planar, columnar cellular, columnar dendritic, equiaxed dendritic), which is controlled by the solidification process. By numerical simulation, it is noted that along with solidification, the solidification mode of the alloy transforms from cellular to columnar dendritic and finally to equiaxed dendritic. Through increasing melt temperature and mold preheating, the range of equiaxed dendrite could be decreased, which helps to extend the region of oriented pore structure.%采用金属-气体共晶定向凝固工艺(GASAR工艺),制备气孔定向排列的多孔铜锰合金,并研究气孔结构的变化.结果表明:这种变化主要取决于合金的凝固模式(平面凝固、柱状胞晶凝固、柱状枝晶凝固、等轴枝晶凝固),而合金凝固模式由合金的凝固过程决定.通过数值模拟发现,随着合金凝固的进行,合金的凝固模式从胞晶凝固向柱状枝晶凝固过渡,最终变为等轴枝晶凝固.通过升高合金熔体温度和铸型的预热温度,可以缩小等轴枝晶凝固的范围,扩大定向生长气孔的区域.