Using copper-mould spray casting techniques combined with vacuum induction melting

non equilibrium solidified samples of AZ91 magnesium alloy containing nano SiC particles were prepared at the large cooling rate.After solid solution treatment at 400 ℃for different time

effects of nano SiC particles on microstructure and thermal stability for AZ91 magnesium alloy were analyzed.The results show that grains of AZ91 magnesium alloy with nano SiC particles are refined greatly by copper-mould spray casting.Grain sizes can be refined to 5μm by copper mould casting with 2mm in diameter and 1% SiC nano-particles.SiC nano-particles play a role as a heterogeneous site under alloy solidification interface migration.Consequently

the combined effect refines grain size.As for the refined magnesium alloy after solid solution treatment at 400℃for different time

the average grain size of spray casted magnesium alloy with SiC particles is increased slowly

and it reaches only 12μm even after holding for 8h

indicating the effective increase of thermal stability for metastasable microstructure.