Al-5Ti-1B对ZL101A合金晶粒细化效果影响

Effect of Al-5Ti-1B Grain Refiner on Grain Refinement of ZL101A Alloy

Al-5Ti-1B中间合金常用作ZL101A合金的细化剂,然而,在熔体长时间保温后,其细化效果逐渐减少。本文研究了Al-5Ti-1B对ZL101A合金晶粒的细化效果。结果表明,熔体保温90 min后Al-5Ti-1B中间合金明显出现衰退,α初晶明显粗化,而在冷却曲线上表现为初晶过冷度明显升高。Al-5Ti-1B的异质形核作用源于TiAl_3粒子,其细化剂的衰退是多种因素综合影响的结果。因此,建议ZL101A合金熔体保温时间不应超过1 h。

Al-5Ti-lB intermediate alloys are often used as grain refiners in Al-Si alloys. However, their effectiveness decreases after a prolonged melt holding time, an experiment was conducted to study the effects of Al-5Ti-1B grain refiner on grain refinement of ZL101A alloy. The results show that, after melt holding time is longer than 90 min, the effectiveness of Al-5Ti-IB grain refiner decreases, α primary grains coarsen obviously, and the nucleation undercooling from the cooling curves is higher. Due to heterogeneous nucleation effect of TiA13, fading of Al-5Ti-IB grain refiner is affected by many factors, therefore, the experimental results in the present work indicate that the melt holding time of ZL101A alloy should not exceed lh.