Variation in Hydrogen Content of Al-Si Hypoeutectic Melts with Strontium Addition H. Guthy, S. Shankar, M. Makhlouf The Advanced Casting Research Center, USA The hydrogen content of commercial hypoeutectic aluminum-silicon alloys modified with varying amounts of strontium and sodium was quantified. The results indicate a significant change in the hydrogen content of the melts with the level of modification. Contrary to current views, accurate and repeated measurements using ALSCAN(tm) indicate a reduction in hydrogen levels with modification. The observed reduction in hydrogen levels is explained in terms of measurable changes in the melt's surface energy due to modifier additions. Based on these findings, a mechanism is proposed to explain the relationship between modification and hydrogen content in hypoeutectic aluminum silicon alloys. Understanding the relationship between silicon modification and the hydrogen content of molten aluminum alloys can play a significant role in mitigating microporosity in components that are cast from these alloys. |