Optimizing the composition of master alloys for grain refining aluminium

摘要: Aluminium alloys are grain refined by inoculating the melt with specially prepared master alloys, called Tibor which contain high levels of Ti and B. Such refiners commercially available in various chemical compositions widely used aluminium smelters, alloy makers even foundries. Systematic studies have been done to evaluate refining potency several these commercial alloys. The general finding had that inoculation level, i.e., content B matrix after inoculation, has a marked effect on resulting size. solution will readily combine form TiB{sub 2} under conditions hence, presence free simultaneously is an unlikely prospect. Depending prevailing B/Ti ratio, either Ti, or B, likely occur except when ratio ideal stoichiometric atom 2/1 for 2}. Commercial ratios lower than 2/1, they excess Ti. Evaluations shown essential efficient refinement. On other hand, eliminating totally frommore » refiner also diminishes its potency. Therefore, plays important role improving refinement but, too much it may lessen effect. An optimum then exist. This study was undertaken determine this value.« less