Understanding grain refining and anti Si-poisoning effect in Al-10Si/Al-5Nb-B system  

作　　者：Yang Li Ying Jiang Bin Liu Qun Luo Bin Hu Qian Li 

机构地区：[1]Materials Genome Institute,State Key Laboratory of Advanced Special Steels,Shanghai Key Laboratory of Advanced Ferrometallurgy,School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China [2]China Science Lab,General Motors Global Research and Development,56Jinwan Road,Shanghai 201206,China

出　　处：《Journal of Materials Science & Technology》2021年第6期190-201,共12页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(51871138);Science and Technology Commission of Shanghai Municipality(19010500400);the 111 project(No.D16002)。

摘　　要：Grain refinement is critical for fabricating high-quality Al-Si casting components in the application of automobile and aerospace industries,while the well-known Si-poisoning effect makes it difficult.Nbbased refiners offer an effective method to refine Al-Si casting alloys,but their anti Si-poisoning capability is far from being understood.In this work,the grain refining mechanism and the anti Si-poisoning effect in the Al-10 Si/Al-5 Nb-B system were systematically investigated by combining transmission electron microscope,first-principles calculations,and thermodynamic calculations.It is revealed that NbB_(2)provides the main nucleation site in the Al-10 Si ingot inoculated by 0.1 wt.%Nb Al-5 Nb-B refiner.The exposed Nb atoms on the(0001)NbB_(2)and(1-100)NbB_(2)surface can be substituted by Al to form(Al,Nb)B_(2)intermedia layers.In addition,a layer of NbAl_(3)-like compound(NbAl_(3)')can cover the surface of NbB_(2)with the orientation relation of(1-100)[11-20]NbB_(2/)/(110)[110]NbAl_(3)'.Both of the(Al,Nb)B_(2)and NbAl_(3)'intermedia layers contribute to enhancing the nucleation potency of NbB_(2)particles.These discoveries provide fundamental insight to the grain refining mechanism of the Nb-B based refiners for Al-Si casting alloys and are expected to guide the future development of stronger refiners for Al-Si casting alloys.

关 键 词：Al-Si casting alloys Grain refinement Niobium diboride Interface Anti Si-poisoning 

分 类 号：TG136.1[一般工业技术—材料科学与工程]