Measurement And Calculation Of The Solid-liquid Interface Energy Of Metals

Knowing the accurate solid-liquid interfacial energy is great help for understanding and grasping procedure of the alloy solidification and nucleation.This article mainly deals with the solid-liquid interfacial energies of aluminum alloy and the germanium alloy through different experimental methods.Based on the free volume theory derived excess vibrational entropy and excess positional entropy, combined with Miedema model, the solid-liquid interfacial energies Al-Mg, Al-Cu, Al-Ni and Al-Ti alloys have been predicted. It is found that the predicted results of solid-liquid interface energy for aluminum alloys are in agreement with the experimental results reported. The error is 1.822%-6.655%.By using grain boundary groove method, the solid-liquid interface energy between Al solid solution and Al-Mg melt has been measured. After the sample was hold for time 14 days, the equilibrated grain boundary groove shapes for the Al solid solution in Al-Mg melt were successfully obtained. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient for Al solid solution in Al-Mg liquid solutions has been determined to be 1.79845×10-4K/min. The solid-liquid interface energy between solid solution and Al-Mg melt has been obtained to be 0.16472J/m2 from the Gibbs-Thomson equation, which is in agreement with the experimental value reported and the calculated result.Adopting molten glass denucleating and cycle superheating technology, the Ge-0.1%wtAl alloy melts were highly undercooled. The factors to influenc undercooling such as the chemical composition of glass, the temperature, the holding time, and the number of cycle overheating were investigated. It is found that the chemical composition of glass is the most important factor affecting the undercooling. By denucleating Ge-0.1%wtAl alloy in glass, the maximum undercooling obtained was 333.3K. In terms of the grain morphology, it is determined that the critical undercoolings for Ge-0.1% wtAl alloy from lateral growth to intermediary growthΔT* and that from intermediary growth to continuous growthΔT** are 85.4 K and 163.4K, respectively. On this basis, the solid-liquid interface energy of Ge-0.1%wtAl alloy has been predicted by the critical growth-transition undercooling methord. Direct expression among the homongenous nucleation undercooling, the physical and chemical parameters, and the solidification parameters of Ge-0.1%wtAl alloy has been acquired.