Phase selection during solidification of undercooled Ni_(70.2)Si_(29.8) eutectic alloy  

作　　者：Yiping Lu Tingju Li Fu Yabo Sun Jianbo LUO Dawei Gencang Yang Yaohe Zhou 

机构地区：[1]Laboratory of Special Processing of Raw Materials, Key Lab of Materials Modification by Laser, Electron and Ion Beams, Ministry of Education of China Dalian University of Technology, Dalian 116024, China [2]School of Materials Seience and Engineering, Jiamusi University, Jiamusi 154007, China [3]State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi＇an 710072, China

出　　处：《Progress in Natural Science:Materials International》2009年第11期1619-1624,共6页自然科学进展·国际材料（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.50395103)

摘　　要：High undercooling （about 392 K） was achieved in the bulk eutectic Ni70.2Si29.8 alloy melt through glass fluxing combined with cyclic superheating. It is found that the metastable phases Ni3Si2 and NiSi are obtained through slow post-solidification when undercooling exceeds 240 K. The metastable phases are confirmed by using the method of X-ray diffraction and differential scanning calorimetry （DSC）. Based on the principle of the free energy minimum and the transient nucleation theory, the phase selection of melt is investigated with regard to the metastable phases formation in the bulk undercooled eutectic Ni70.2Si29.8 melts. The formation of metastable phases from undercooled Ni70.28i29,8 melts is ascribed to competitive nucleation with the undercooling, i.e. high undercooling facilitates the preferential nucleation of metastable phases.在冷却下面的高度(大约 392 K ) 在体积被完成最容易溶解的 Ni <sub>70.2</sub > Si _29.8 合金通过与周期的过热相结合的玻璃 fluxing 融化。这被发现亚稳的阶段 Ni <sub>3</sub > Si ₂ 并且非最后被获得通过慢团结以后什么时候在冷却下面超过 240 K。亚稳的阶段被使用 X 光检查衍射和微分扫描热量测定(DSC ) 的方法证实。基于免费精力最小和短暂成核理论的原则，阶段选择融化在凉下来的最容易溶解的 Ni <sub>70.2</sub 下面在体积关于亚稳的阶段形成被调查 > Si _29.8 融化。从在凉下来的 Ni <sub>70.2</sub 下面的亚稳的阶段的形成 > Si _29.8 融化被归功于到竞争成核与在冷却下面，即在冷却下面的高度便于亚稳的阶段的优先的成核。

关 键 词：UNDERCOOLING Eutectic alloy Metastable phase NUCLEATION 

分 类 号：TG111.4[金属学及工艺—物理冶金] TG146.15[金属学及工艺—金属学]