Dissolution of Solid Aluminium in Molten Al-Si-Mg Alloys

Abstract

A basic study of aluminum brazing has been made of the reaction between aluminum base metal and Al-Si-Mg brazing filler metals from the viewpoint of dissolution kinetics. The dissolution of solid aluminum in molten Al-Si-Mg alloys was studied under static and isothermal conditions. The solid aluminum cylinders were immersed in molten Al-12.6%Si-Mg alloys with magnesium increasing up to 5% under the argon atmosphere in the temperature range from 571 to 603°C. The rates of dissolution of solid aluminum in molten Al-Si-Mg alloys were dependent on the temperature and the magnesium concentration. The obtained values of dissolution rate constant increased with increasing magnesium concentration in solutions and temperature. The natural convections were produced by the large density defferences between the boundary layer adjacent to the solid aluminum and the molten alloy. Consequently, the natural convections exerted an influence on the dissolution phenomenon. It was concluded that the rates of dissolution were controlled by the diffusion process of dissolved atoms through the boundary layer adjacent to the dissolving surface of the solid aluminum.
The dissolution of solid aluminum in molten Al-Si-Mg alloys was studied under static and isothermal conditions. The rates of dissolution of solid aluminum in molten Al-Si-Mg alloys were dependent on the temperature and the magnesium concentration. The obtained values of dissolution rate constant increased with increasing Mg concentration in solutions and temperature. It was concluded that the rates of dissolution were controlled by the diffusion process in the solutions.