Phase-selection and metastable phase formation in highly undercooled eutectic Ni_(78.6)Si_(21.4)alloys  

作　　者：LU Yiping YANG Gencang YANG Changlin WANG Haipeng ZHOU Yaohe 

机构地区：[1]State Key Laboratory of Solidification Processing, Northwestern Polyteehnical University, Xi＇an 710072, China [2]Department of Applied Physics, Northwestern Polytechnical University, Xi＇an 710072, China

出　　处：《Progress in Natural Science:Materials International》2006年第3期287-291,共5页自然科学进展·国际材料（英文版）

基　　金：Supported by National Natural Science Foundation of China (Grant No. 50395103)the Doctorate Foundation of Northwestern Polytechnical University

摘　　要：A large undercooling （250 K） was achieved in eutectic Ni78.6Si21.4 melt by the combination of molten-glass denucleation and cyclic superheating. The metastable phase formation process in the bulk undercooled eutectie Ni78.6Si21.4 melts was investigated, With the increase of undercooling, different metastable phases form in eutectic Ni78.6Si21.4 melts and part of these metastable phases can be kept at room temperature through slow post solidification. Under large undercooling, the metastable phases β2-Ni3Si, Ni31Si12 and Ni3Si2 were identified. Especially, the Ni3Si2 phase was obtained in eutectic Ni78.6Si21.4 alloy for the first time. Based on the principle of free energy minimum and transient nucleation theory, the solidification behavior of melts was analyzed with regard to the metastable phase formation when the melts were in highly undereooled state.在冷却下面大的 A (250 K ) 在最容易溶解的 Ni <SUB>78.6</SUB 被完成 > Si <SUB>21.4</SUB> 由熔融眼镜的 denucleation 并且周期的过热的联合融化。在在凉下来的最容易溶解的 Ni <SUB>78.6</SUB 下面的体积的亚稳的阶段形成过程 > Si <SUB>21.4</SUB> 融化被调查。随增加在冷却下面，在最容易溶解的 Ni <SUB>78.6</SUB 的不同亚稳的阶段形式 > Si <SUB>21.4</SUB> 融化并且这些亚稳的阶段的部分能在房间温度被保留通过慢团结以后。在下面在冷却，亚稳的阶段 b2-Ni3Si， Ni31Si12 和 Ni3Si2 下面大被识别。特别， Ni3Si2 阶段在最容易溶解的 Ni <SUB>78.6</SUB 被获得 > Si <SUB>21.4</SUB> 合金第一次。基于最小的免费精力和短暂 uncleation 理论的原则，团结行为融化关于亚稳的阶段形成被分析 melts 什么时候高度在在下面，使状态凉下来。

关 键 词：UNDERCOOLING molten-glass metastable phase rapid solidification 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TG156.1[金属学及工艺—金属材料]