When sourcing aluminum master alloys (such as AlTiB, AlSr, or AlSi), the price is heavily dictated by the chemical composition accuracy and the microstructure. You must verify the elemental content percentage (e.g., Ti 5%, B 1%) and ensure the impurity levels (like Fe, Si, or V) are within strict limits to avoid contaminating the final melt. High-quality alloys should feature fine, uniformly distributed intermetallic phases to ensure effective grain refinement or modification, which justifies a premium price over generic alternatives.