Taking TiO2 powders as inoculant,the effect of the TiO2 powders on the refinement and modification of α-Al and eutectic Si phase in A356 was studied.The results show that when the optimum addition of TiO2 is 0.5wt％,the size ofα-Al grain can be reduced to 20 μm,and the morphology of eutectic silicon are modified from needle form to short stick even spherical form.Accordingly,the value of Brinell hardness is increased by 25％to 67.9 HBW.The analysis thinks that the α-Al phase and eutectic Si phase are refined and modified by the aluminum alloy melt and TiO2 in situ generated γ-Al2O3,and the performance of the material is improved by the synergistic particle strengthening of γ-Al2O3.
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