Activity of strontium in liquid Sr-modified Al-7Si alloy

ABSTRACT

In the present study, the Henrian activity coefficient of strontium ${\gamma }_{\mathrm{S}\mathrm{r}}^{{ }^{\circ }}$, dissolved in liquid Al-7Si alloy at 725–730°C has been determined to be in the order of 10⁻², using the numerical thermodynamic analyses. By knowing the ${\gamma }_{\mathrm{S}\mathrm{r}}^{{ }^{\circ }}$, formation of the compounds, Sr(OH)₂ and SrH₂ through the reaction of dissolved elements in Al-7Si alloy melt has been analysed. The results indicated that the free energy of the formation reaction of Sr(OH)₂ and SrH₂ in the alloy melt are positive at different temperatures, showing that these compounds may not be formed in the liquid aluminium alloys.

KEYWORDS:

• Al-7si alloy
• Sr-modification
• activity coefficient
• standard gibbs free energy

Disclosure statement

No potential conflict of interest was reported by the authors.