TiO_(2)变质对A356铝合金微观组织的影响

Effect of TiO_(2)Modification on Microstructure of A356 Aluminum Alloy

以TiO_(2)粉末为变质细化剂,研究了其对A356铝合金预处理后α-Al相和共晶Si的细化变质作用。结果表明,当TiO_(2)的最佳添加量为0.5wt%时,α-Al晶粒的二次枝晶间距可降至20μm,共晶Si组织呈短棒状和球状;此时,合金的布氏硬度较未变质前提高了25%,达到67.9 HBW。分析认为,铝合金熔体与TiO_(2)原位生成γ-Al_(2)O_(3)同时细化变质了α-Al相和共晶Si相,协同γ-Al_(2)O_(3)的颗粒增强作用共同提高了材料的性能。

Taking TiO_(2)powders as inoculant,the effect of the TiO_(2)powders on the refinement and modification ofα-Al and eutectic Si phase in A356 was studied.The results show that when the optimum addition of TiO_(2)is 0.5wt%,the size ofα-Al grain can be reduced to 20μm,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 theα-Al phase and eutectic Si phase are refined and modified by the aluminum alloy melt and TiO_(2)in situ generatedγ-Al_(2)O_(3),and the performance of the material is improved by the synergistic particle strengthening ofγ-Al_(2)O_(3).