Ab initio molecular dynamics simulation of heterogeneous nucleation behavior at TiC/Ni solid-liquid interface
In this work,the heterogeneous nucleation behavior of atoms and the electronic structure of four TiC/Ni solid-liquid interfaces were comprehensively analyzed by using ab initio molecular dynamics(AIMD)and density functional theory(DFT)simulations.The mechanism of TiC promoting heterogeneous nucleation of Ni was then further discussed.The results show that pre-nucleation layer(PNL)of Ni can be induced by TiC(100),[Ti]-TiC(111)and[C]-TiC(111)substrates,and the arrangement of interlayer and in-plane ordering of the PNL at the interface is:[Ti]-TiC(111)/Ni＞[C]-TiC(111)/Ni＞TiC(100)/Ni.The strong interactions and chemical bonds between[Ti]-TiC(111)and the Ni atoms of PNL lead to the highest order degree of PNL.However,the TiC(110)substrate cannot induce the formation of pre-nucleation layer,and its ability to promote heterogeneous nucleation of Ni is the weakest compared to the above three substrates.During the cooling process,the remaining Ni atoms in the liquid phase gather into clusters on the outside of the PNL,which are induced as a transition layer on TiC(100),[Ti]-TiC(111)and[C]-TiC(111)substrates,and form a stable crystal nucleus as the temperature decreases.This provides quantitative theoretical data to explore the mechanism by which TiC particles promote heterogeneous nucleation of nickel-based superalloys.
TiC/Ni solid-liquid interfacepre-nucleation layerheterogeneous nucleationab initio molecular dynamics simulation
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