Kinetics of modifier dissolution in aluminum-based melts

Abstract

This study investigates the dissolution kinetics of pure metals (Cu, Zr, Ti) and crystalline modifiers of the Al–Zr and Al–Cu–Zr–Ni systems in the melt of high-strength aluminum alloy B95. The relevance of the research stems from the limited understanding of the interaction mechanisms between multicomponent master alloys and liquid aluminum, which constrains the ability to control the structure and properties of cast products. The aim of the work is to establish the dissolution patterns of various types of modifiers in the melt, considering the effects of temperature, holding time, and phase composition. Experimental investigations were conducted using the rotating disk method, which ensures a uniformly accessible contact surface with the melt. The contact time between solid samples and the aluminum-based melt ranged from several seconds to one hour. Mass loss due to oxidation or evaporation was determined through control experiments, where samples underwent all stages except dissolution. Specific dissolution rates of the components were determined and correlated with the physicochemical properties of the materials. It was found that copper exhibits the highest dissolution rate among the pure metals studied (18.6 kg/m²·s), while zirconium and titanium dissolve approximately ten times slower. Crystalline modifiers dissolve significantly faster than their corresponding pure metals. In particular, samples of the Al–Cu–Zr–Ni system lose half their mass within 30 seconds of contact with the melt at 750 °C, indicating a strong influence of structural factors on the dissolution process. The scientific novelty of the work lies in the quantitative comparison of dissolution rates between pure metals and multicomponent master alloys, as well as in identifying the role of phase transformations and surface activity in the dissolution dynamics. The results expand existing concepts of modifier–melt interaction mechanisms and can be applied to optimize alloying and modification regimes for aluminum alloys in industrial practice.