Dissolution of particles in binary alloys: part II. experimental investigation on an Al-Si alloy

A detailed experimental study of the dissolution kinetics of Si particles in an Al-Si alloy has been carried out in order to test the validity of the two models presented in the accompanying article.1] In these models, the dissolution kinetics are dependent on the particle size distribution of the alloy. An alloy with composition C_o = 0.77 at. pct Si was heat-treated in order to obtain rather coarse spherical particles (1 to 10 μn). The size distribution of the particles was found to be close to the log-normal distribution. At high temperatures, when the solvus concentration was well above C_o, the experimental values were very close to the values of the model which predicted the highest dissolution rates. At lower temperatures, when the solvus concentration was closer toC _o, the experimental values lay in between the values predicted by the two models. The results clearly demonstrate that a size distribution of particles must be included in the model if an accurate prediction of the dissolution kinetics is to be achieved.