Optimal modifying and refining processes for A356 aluminium alloys

摘要

The influence of Ti, B, RE (cerium-rich mixtures of rare earth) and Sr, applied in modification and refining processes, on A356 aluminum alloys has been studied with the aids of OM, etc. The results show that the grain refining efficiency of Grain-Refining Aluminium Ingot (GRAI) and Al-Ti master alloys is similar. But the Ti addition from GRAI has lower costs than that with Al-Ti master alloys. So A356 aluminum alloys produced with GRAI are feasible in economy.Grain refining with GRAI with 0.01%Ti plus additional 0.03% B offers significant advantages over that from GRAI with 0.1% Ti only in A356 aluminum alloys, which made the dendrite α (Al) grain structure transform into equiaxed α (Al) grain structure, plus a partially modified eutectic silicon structure. RE addition to A356 aluminum alloys with Sr modifier is enable to achieve small DAS,reduced pores, well-refined fibrous silicon, small and dispersive eutectic colonies.