Phase-field Simulation Of The Evolution Of Al-Ni Liquid/Solid Interface

The stratified metal is a material obtained by metallurgical bonding of two or more different kinds of metal interfaces by mutual diffusion of atoms,and its function that cannot be realized by a single metal.Al and Ni,as metals that are easily obtained from nature,are widely used in industrial society and have considerable prospects.Compared with the long-time solid-solid interface recombination method,the most effective composite mode of Al-Ni interface is a liquid-solid interface composed of solid Ni substrate and liquid Al contact,which forms an intermetallic compound by diffusion reaction to realize the metallurgical bonding between the interface.It is necessary to regulate the liquid-solid interface structure,achieve a strong metallurgical bond at the interface,understand the microscopic formation mechanism of the liquid-solid interface and the evolution mechanism of intermetallic compounds.In order to investigate the micro-formation mechanism of Al-Ni liquid-solid interface and the evolution mechanism of intermetallic compounds,firstly,the in-situ dynamic characterization of Al-Ni liquid/solid interface microstructure evolution was carried out by synchrotron radiation imaging technology,and the results were used to verify the multi-phase field model.Secondly,the KKSO multi-phase field model is used to simulate and analyze the morphology evolution of Al₃Ni intermetallic compounds during the diffusion reaction of Al-Ni/liquid-solid interface at 1123K.The Al₃Ni intermetallics under different parameters are discussed to investigate the evolution mechanism of compounds.Finally,the Moelans model was used to simulate and analyze the growth and maturation process of Al₃Ni₂ grains under the Al-Ni/liquid-solid interface state at 1123K,and the second phase particles which did not react were studied during the Al₃Ni₂ grain maturation process to find their influences on the morphology of Al₃Ni₂ grains.The main research results of this study are as follows:?1?Both the grain boundary diffusion coefficient and the Al₃Ni/Al liquid/solid interface energy affect the morphology of Al₃Ni grains.The grain boundary diffusion coefficient has a significant effect on the thickness of the Al₃Ni intermetallic compound layer,while the Al₃Ni/Al liquid/solid interface energy has a significant effect on the size of the single Al₃Ni grain and the upper surface morphology of the Al₃Ni intermetallic compound.?2?During the evolution of Al₃Ni phase,the Al₃Ni grains in the initial stage rapidly expand on the base phase Al₃Ni₂.While the thickness of the Al₃Ni intermetallic compound layer increases significantly in the growth stage.?3?In the process of Al₃Ni₂ grain maturation,the difference in the volume fraction of the unreacted second phase hard particles will affect the intensity of the arrangement,which affects the pinning effect on the grain boundaries and is reflected on the average grain size of Al₃Ni₂.?4?Under the same volume fraction,the size of a single unreacted second phase particle affects the surface energy at the grain boundary and the number of particles pinned at the grain boundary.Under the combined effect of these two factors,the average size of Al₃Ni₂ grains will change.