Study on crystallization and microstructure for new series of Al–Sn–Si alloys

摘要: Abstract The crystallization behaviors and microstructure for new series of Al–Sn–Si alloys have been investigated with the aids OM, SEM, XRD DTA in paper. phase transformations processes, solidification structure its control method were determined. It was first proposed that belong to ternary eutectic system, equilibrium diagram system inferred. Influences Sn Si content, homogenization treatment on ascertained. spheroidization model β(Sn) phases proposed. During alloys, at first, primary grains separate from liquid (L→α(Al)); then binary forms (L→α(Al)+Si); finally, reaction occurs temperature about 225°C (L→α(Al)+Si+β(Sn)). consists α(Al), phases. attach themselves distribute matrix grain boundary as near-network structure. Modification can not refine only α(Al) phases, but also make well distributed. gathered spheroidized around silicon particles which act nuclei during homogenization. ‘peritectic-type’ island surrounded tin formed. Tin thickness increases increasing content or decreasing contents. ratio (Sn/Si) influences volume fraction distribution Only Sn/Si range 3∼4, best