Study On Temperature Or Composition-Dependent Surface Tension Theoretical Characterization Method Of Liquid Alloys

Surface tension is the core element to leading the surface or interface properties of the materials,and it is the key research object of metallurgy,materials,surface science,and interface colloids.For alloy materials with high melting points,the surface tension in the high-temperature molten state dominates the mass transfer process of the liquid alloy and is a key parameter that determines the properties of alloy materials.The surface tension of liquid alloy is mainly affected by the temperature and concentration of components.Therefore,understanding the evolution law of the surface tension of liquid alloy with temperature/concentration of components,and reasonably characterizing the surface tension of liquid alloy with temperature/concentration of components have always been the focus and difficulty in casting,metallurgy,and welding,etc.The corresponding research has important guiding significance for improving the properties of alloy materials and preparing new materials.In this dissertation,the following theoretical characterization research of temperature/component-dependent surface tension of liquid alloy materials has been carried out:(1)Based on the equivalence principle of force-heat energy density,we established a theoretical characterization model of temperature-dependent surface tension of liquid alloys.The predicted results of the model are in good agreement with the available experimental results.This model established a quantitative relationship of temperaturedependent surface tension,cohesive energy,and thermal expansion coefficient.The model does not require fitting parameters,and all parameters of materials can be easily and conveniently obtained from materials manuals or literature.Compared with the empirical models of other scholars,our model has obvious advantages in modeling ideas,physical meaning,etc.And it also provides a new and simple method to predict the temperature-dependent surface tension of liquid alloys.(2)Based on the equivalence principle of force-heat energy density,through the equivalence between the binding energy of the intermetallic compound cluster and the cohesive energy of materials,a theoretical characterization model about the componentdependent surface tension of the liquid alloy materials was established.And the model prediction results are in good agreement with the available experimental results.This model can be used to analyze the distribution relationship of different components in the surface phase and bulk phase,and it explains the reason why the surface tension of the liquid alloy materials changes nonlinearly with the change of component concentration.Then,combine the model with the theoretical characterization model of temperaturedependent surface tension of liquid alloys established above,we established a theoretical characterization model which can simultaneously consider the coupling effects of temperature and component concentration on the surface tension of liquid alloys.The model can predict the surface tension of liquid alloy in a wide temperature range and the whole component concentration only by the surface tension of alloy and pure component at any reference temperature.And the prediction result is in good agreement with the experimental result.Our work provides suggestions for improving the properties of alloy materials and the preparation of new materials.