凝固模式对Gasar多孔Cu-Cr合金结构及组织影响  

Influence of solidification mode on gas pore structure and microstructure of Gasar porous Cu-Cr alloy

作　　者：宋群玲[1,2] 金青林[1] 李再久[1] 杨天武[1] 蒋业华[1] 周荣[1] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]昆明冶金高等专科学校冶金材料学院,云南昆明650033

出　　处：《材料热处理学报》2015年第3期15-20,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51164018);云南省教育厅基金(2012Y337)

摘　　要：在0.6 MPa纯H2气氛中,采用金属/H2共晶定向凝固(Gasar)技术制备得到Gasar多孔Cu-x Cr合金。研究了Cr含量、凝固模式以及凝固速率对Gasar多孔合金气孔结构和显微组织的影响。结果表明,当合金以平面、胞状及柱状枝晶凝固时,Gasar多孔Cu-x Cr合金能获得定向生长气孔。当凝固方式转变为等轴枝晶凝固时,定向生长气孔发生中断。Gasar多孔Cu-x Cr合金(x=0.8%、1.3%)气孔在共晶相前沿析出,与共晶组织协同定向生长。随Cr含量增加,共晶组织体积百分比增加,孔隙率和孔圆整度进一步增加;随多孔Cu-1.3 Cr合金试样凝固高度增加,凝固速率下降,界面生长方式转变为等轴晶生长方式,则无法得到定向生长气孔。Gasar porous Cu-x Cr alloys were fabricated by a metal / hydrogen unidirectional solidification method under a hydrogen gas pressure of 0. 6 MPa. The effect of the chromium content,solidification mode and solidifying velocity on the pore structure and microstructure were investigated. The results show that an ordered pore structure can be obtained when the microstructure is composed of cellular or columnar dendritic grain structure. The ordered pore structure is deteriorated when equiaxed dendritic structure appears. The pores are generated at the eutectic fronts. With the increasing Cr content,the amount of eutectic microstructure,porosity and roundness of the pores increase. Solidifying velocity decreases with the increasing of the height of porous Cu-1. 3Cr alloy,and an ordered pore structure could not be formed with equiaxed crystal in solid-liquid interface.

关 键 词：Gasar 多孔Cu-Cr合金 凝固速率 共晶组织 凝固模式 

分 类 号：TG291[金属学及工艺—铸造]