Al-5Ti-1B细化剂添加量对含铈铸造铝合金组织和拉伸性能的影响

Effect of Al-5Ti-1B Refiner Addition Amount on Microstructure and Tensile Properties of Cast Aluminum Alloy Containing Ce

在添加质量分数0.1%铈的基础上,对比研究Al-5Ti-1B细化剂质量分数(00.4%)对A356铸造铝合金组织及拉伸性能的影响。结果表明:随着Al-5Ti-1B细化剂含量的增加,α-Al树枝晶的平均二次枝晶间距先降后增,当细化剂的质量分数为0.2%时,平均二次枝晶间距最小,为37.3μm;添加适量细化剂能促使共晶硅由狭长纤维状向粗短棒状的转变,从而降低共晶硅的等效直径和长宽比,过量细化剂则会引起共晶硅的尖锐化;添加细化剂后,铝合金的抗拉强度和断后伸长率均提高,且随着细化剂含量的增加呈先增后降的趋势;添加质量分数0.2%细化剂时铝合金的综合变质效果最佳,此时铝合金的拉伸性能最佳,抗拉强度和断后伸长率较未添加细化剂时的分别提高了20.7%和66.7%。

On the basis of adding 0.1 wt% Ce,the effect of the Al-5 Ti-1 Brefiner content(0 wt%-0.4 wt%)on the microstructure and tensile properties of A356 cast aluminum alloy was comparatively studied.The results show that with increasing content of Al-5 Ti-1 Brefiner,the average secondary dendrite spacing of α-Al dendrite decreased first and then increased,and reached the smallest value of 37.3μm when the content of refiner was0.2 wt%.The proper amount of refiner promoted the eutectic silicon shape changing from long and narrow fibrous to thick and short rods,and resulted in the reduction of equivalent diameter and aspect ratio of eutectic silicon;but the excessive amount of refiner caused the sharpening of eutectic silicon.After adding the refiner,the tensile strength and percentage elongation after fracture of the aluminum alloy all increased,and increased first and then decreased with increasing refiner content.The comprehensive modification effect of the aluminum alloy after adding 0.2 wt%refiner was the best,and the tensile properties were the best;the tensile strength and percentage elongation after fracture increased by 20.7% and 66.7%compared with those without adding refiner,respectively.