几种典型细化剂对A356合金的细化作用

Refinement Effects of Some Typical Refiner on A356 Alloy

研究了几种常用的AlTiB、AlTiC、AlTi和Al3B细化剂微观组织及其对A356合金的细化效果。结果表明,对于4种AlTiB细化剂,第二相的尺寸和分布对细化效果有一定影响,荷兰产AlTiB细化剂Al3Ti尺寸小,TiB2呈弥散分布,细化后晶粒尺寸最小,在加入量(质量分数,下同)为0.2%,保温时间30min时,尺寸为500μm。对于不同系列晶粒细化剂,在加入量为0.2%和0.5%时,AlTiB的细化效果均为最好。较快的凝固速度下,各种细化剂的细化效果无明显差别;凝固速度较慢时,Al3B细化剂的细化效果较好。

Microstructures of some typical refiners, including Al-Ti-B, Al-Ti-C, Al-Ti and Al-B master alloy, were observed and their refinement effects on A356 alloy were examined. The results show that secondary phase size and distribution in A356 alloy can affect refinement effect with Al-Ti-B master alloy. 4# refiner from the Holand with small Al_3Ti size and uniformly distributed TiB_2 have the most refining effects on the A356 alloy among these refiners, in which the size of primary Si phase is 500 μm at holding for 30 min with 0.2% addition. As 0.2% and 0.5% additions for these four kinds of refiners, Al-Ti-B has the most refinement effects on the A356 alloy. The refinement effects had no obvious difference at a high cooling rate while Al-3B refiner is better at lower cooling speed for the four kinds of refiners.