Grain refinement of DIN226 alloy at high titanium and boron inoculation levels
- Nanyang Technological Univ., Singapore (Singapore)
The grain refinement of aluminium alloy castings is normally achieved by melt inoculation with Ti and B in the form of grain refining master alloys. The presence of excessive Ti over the stoichiometry for TiB{sub 2} is a key factor for effective grain refinement of pure Al and dilute alloys. Grain refinement of casting alloys containing high levels of Si are known to be difficult. The Si is thought to hinder the role of Ti and/or promote the role of B so that the optimum Ti:B ratio requirement established for dilute aluminium alloys does not apply to high-Si casting alloys. These works are however done at Ti levels less than the 0.15 wt% which is the peritectic composition in Al-Ti phase diagram. Little work has been done to evaluate the factors that affect the grain refinement of Al-Si casting alloys at Ti additions higher than 0.15 wt %. Although, such high levels of Ti additions are not normally used in grain refinement practice, they may help in understanding the mechanisms of grain refinement. The objective of this work, therefore, is to study the effect of Ti:B ratio and the total Ti content on the grain refinement of a commercial, hypo-eutectic Al-Si casting alloy at Ti addition levels equal to or higher than 0.15 wt%.
- OSTI ID:
- 382489
- Journal Information:
- Scripta Materialia, Vol. 35, Issue 7; Other Information: PBD: 1 Oct 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Grain refinement mechanisms of hypoeutectic Al-Si alloys
Study of the mechanism of grain refinement of aluminum after additions of Ti- and B-containing master alloys