The Influence Of Mechanical Vibration On The Surface Tension Of Liquid Metal

Surface tension is a important physical and chemical parameter among numeroussubjects include in surface science, material and metallurgical. It has wide relationbetween surface tension with refining and extract of metal, composite and functionalmaterials, plating and coating, biological membrane field. Vibration casting is a processof traditional casting provided with vibration field, This kind of casting process hasbeen widely researched, Surface tension can＇t be ignored in casting process, such asmelting of casting alloy, pouring solidification and forming process, The scholars hascarried out extensive research and discussion about surface tension.It was found that the effect of mechanical vibration on the filling ability, hot crack,degassing, slag inclusion was really exist, but the results are mostly qualitative analysisby theory. The researches about influence factors of surface tension mainly involvestructure of material, temperature, pressure, composition melting point, element,electron density, magnetic and electric field, but few on the study of vibration. Throughthe analysis above, the study mainly include:It has been studied on the measurement method of surface tension, The method ofmaximum bubble pressure method(MBPM) has been improved，It has been realized tomeasure the surface tension under vibration field by the method of vibrating doublecapillaries.The surface tension of Aluminum and A356alloy had been measured through theself-designed device. According to the analysis of pressure curve, it is reasonable tomeasure surface tension using pressure peak of the pressure curve. The surface tensionof Aluminum is0.8542N·m-1,The experiment error is in±0.02N·m-1,the relative error is6.8%.It has been studied about the effect of mechanical vibration on the surfacetension.The experiment result show that surface tension of Aluminum at720℃willdecrease with the frequency of vibration,The surface tension when provide0Hz,20Hz,35Hz,40Hz is0.8542N·m-1,0.7641N·m-1,0.7201N·m-1,0.6612N·m-1,Respectively. The surface tension of Aluminum has decreased0.1930N·m-1whenprovided40Hz vibration frequency. The influence coefficient of vibration frequency is0.0048N·m-1·Hz-1, It has a great influence on the surface tension when compared withtemperature which is0.0002N·m-1·Hz-1commonly. The mechanism of influence on the surface tension is discussed. The surfacetension relates with the distance of atoms, valence electron and charge number based onthe electric double layer theory. The effect of vibration field will increase the rate ofatoms. The atomic distance will be increased at the interface field. Also, the vibrationwill increase opportunity to translate of valence electron, The effect of vibration is aprocess of work from the perspective of thermodynamics. This process will increase theopportunity to contact and interchange which will reduce the imbalance of interface.The surface tension will decrease of the increasing heat because of friction.