Morphological Heredity of Intermetallic Nb_(5)Si_(3)Dendrites in Hypereutectic Nb-Si Based Alloys via Non-Equilibrium Solidification  

作　　者：Yueling Guo Lina Jia Wenjun Lu Hu Zhang 

机构地区：[1]School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China [2]Research Center of Light‑alloy Materials,Frontier Institute of Science and Technology Innovation,Beihang University,Beijing 100191,China [3]Max-Planck-Institut für Eisenforschung,Max‑Planck‑Straße 1,40237 Düsseldorf,Germany

出　　处：《Chinese Journal of Mechanical Engineering》2022年第5期393-400,共8页中国机械工程学报（英文版）

基　　金：National Natural Science Foundation of China(Grant No.51571004).

摘　　要：For hypereutectic Nb-Si based alloys,primary Nb_(5)Si_(3)phases typically grow in a faceted mode during equilibrium or near-equilibrium solidification,which damages the ductility and toughness.To address this issue,here we artificially manipulate the growth morphology of Nb_(5)Si_(3)using electron beam surface melting(EBSM)and subsequent annealing treatments.Results show that such a non-equilibrium solidification pathway enables the transition from faceted growth to non-faceted dendritic growth of Nb_(5)Si_(3),along with evident microstructure refinement,generation of metastableβ-Nb_(5)Si_(3)phases and elimination of chemical segregation.The transformation fromβ-Nb_(5)Si_(3)toα-Nb_(5)Si_(3)and Nb solid solution(Nbss)particles is triggered by the annealing treatment at 1450°C for 5 h.Also,we find the annealing-mediated formation of inherited Nb_(5)Si_(3)dendrites that maintain the dendritic morphology of the original as-solidifiedβ-Nb_(5)Si_(3)dendrites.This work thus provides a feasible routine to obtain thermally stable and refinedα-Nb_(5)Si_(3)dendrites in hypereutectic Nb-Si based alloys.

关 键 词：Nb-Si alloy Intermetallics Nb_(5)Si_(3) Rapid solidification Dendritic growth 

分 类 号：TG146.416[一般工业技术—材料科学与工程]