定向凝固Al-La合金组织性能的研究  

Microstructures and Properties of Directional Solidified Al-La Alloys

作　　者：董晓娟[1] 王自东[1] 张鸿[1] 郑亚虹[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《铸造》2009年第3期217-220,224,共5页Foundry

基　　金：国家重大基础研究项目(2006CB605200)

摘　　要：采用Bridgman定向凝固方法,制备出不同抽拉速度下尺寸分别为Φ6mm×50mm和Φ3mm×50mm的试样棒。对试样组织形貌进行分析,发现了一种由α-Al(暗相)和Al11La3(亮相)两相交替出现的枝晶组织,沿枝晶主干方向成分呈周期性变化,称这种组织为周期性双相枝晶组织;而且这种枝晶组织主干方向与凝固方向一致,证明这种枝晶确实存在。通过分析认为,对流可能是产生这种组织的主要原因。经力学性能测试,试样的压缩性能较好,硬度较高。By adopting Bridgman directional solidification equipment, the AI-35wt. %La alloy samples at different withdrawal rate were prepared, the sizes of which are Ф6mm×50 mm and Ф3 mm×50 mm. The microstructure and phase of the alloys have been studied, and the results show that the dendritic structure during solidification is composed of α-AI （dark phase） alternating with Al11La3 （bright phase）. Along their dendritic stem, the composition of the structure exhibits periodical behavior. This structure is named periodic diphase dendritic structure. And the dendritic stem direction is consistent with the solidification direction, proving that this structure does indeed exist. The formation of this novel structure has possibly been attributed to the presence of convection in the liquid. The mechanical properties were tested, this kind of alloys have a higher compression strength and hardness.

关 键 词：Al-La合金 定向凝固 周期性双相枝晶组织 对流 力学性能 

分 类 号：TG113.26[金属学及工艺—物理冶金]