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Al-3Ti-1B master alloys were prepared at different processing parameters by the reaction of halide salts,and the grain refining response of Al-7Si alloy was investigated with Al-3Ti-B master alloy.The microstructure of master alloy and its grain refining effect on Al-7Si alloy were investigated by means of OM,XRD and SEM.Experimental results show that,the size of Al3Ti particles presented in Al-3Ti-1B master alloys increases with the increase of reaction temperature and decreases with the increase of cooling rate.The grain refining efficiency of Al-3Ti-1B master alloy on Al-7Si alloy is mainly attributed to heterogeneous nucleation of Al3Ti particles,and the morphology ofα(Al)changes from coarse dendritic to fine equiaxed.As a result,Al-3Ti-1B master alloy is prepared by permanent mold,and holding at 800 ℃for 30min,which has better grain refining performance on Al-7Si alloy.
Al-3Ti-1B master alloys were prepared at different processing parameters by the reaction of halide salts, and the grain refining response of Al-7Si alloy was investigated with Al-3Ti-B master alloy. The microstructure of master alloy and its grain refining effect on Al-7Si alloys were investigated by means of OM, XRD and SEM. Experimental results show that the size of Al 3 Ti particles presented in Al-3 Ti-1B master alloys increases with the increase of reaction temperature and decreases with the increase of cooling rate of the grain refining efficiency of Al-3 Ti-1B master alloy on Al-7Si alloy is mainly attributed to heterogeneous nucleation of Al 3 Ti particles, and the morphology of α (Al) changes from coarse to fine equiaxed. As a result, Al- 3Ti-1B master alloy is prepared by permanent mold, and holding at 800 ° C for 30min, which has better grain refining performance on Al-7Si alloy.