The effects of Al-10Sr master alloys on grain refinement of AZ31 magnesium alloy were investigated,and the refinement efficiency of different Al-10Sr master alloys(commercial,solubilized,rolled and remelted+rapidly cooled)was compared and analyzed.The results indicate that the morphology and size of Al4Sr phases in the microstructures of different Al-10Sr master alloys,are of great difference.For the commercial Al-10Sr master alloy,the Al4Sr phases evolve from coarse block shape to relatively fine block shape after being dissolved at 500 ℃ for 4 h and followed by water quenching;but after being rolled at 300 ℃ for 50% reduction or remelted and followed by rapid cooling,the Al4Sr phases mainly exhibit fine granule and fibre shapes.In addition,the different Al-10Sr master alloys can effectively reduce the grain size of AZ31 magnesium alloy,but their refinement efficiency is different.The refinement efficiency of the Al-10Sr master alloy obtained by remelting and rapid cooling is the best,then the rolled,solubilized and commercial Al-10Sr master alloys are in turn.The difference of refinement efficiency for different Al-10Sr master alloys may be related to the dissolution rates of Al4Sr phases with different morphologies and sizes in the melt of AZ31 magnesium alloy.
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