Al3Ti1B1RE细化剂对罐用铝材的细化效果及稀土的作用

Refining Effect of New Al3Ti1B1RE Master Alloy on Aluminum Sheet Used for Pressure Can and Behavior of Rare Earths in Master Alloy

采用XRD,OM,SEM,EDAX等探讨了一种新型Al3Ti1B1RE中间合金细化剂对罐用铝材的细化效果及RE的作用。结果表明,该细化剂对罐用铝材的细化效果优于进口和国产Al5Ti1B,且具有长效性,达6h后仍未见明显衰退,明显提高了该材料的强度和塑性;其细化效果及稳定性好的主要原因是:RE可降低铝液的表面能,增加铝液对细化核心(如TiAl3,TiB2)的润湿性,既充分发挥了异质形核作用,又防止了TiB2聚集沉淀倾向;RE也极易在结晶前沿富集造成成分过冷,阻碍了α Al晶粒生长,并促进其在细化核心上形核;此外RE还兼有一定的净化、细化和变质作用,尤其是净化作用提高了该细化剂的冶金质量。

The refining effect of Al3Ti1B1RE master alloy on aluminum sheet used for pressure can and behavior of mixed rare earths (RE) in master alloy were investigated by XRD, OM, SEM and EDAX, etc. It is found that the refining effect of the refiner on the material has superiority over Al5Ti1B refiner imported from abroad or made in China, and its refining effect still remains after it is added to molten aluminum for 6 h, thus improving the strength and plasticity of the material remarkably. The reason for the excellent refining effect and stability of AlTiBRE refiner is in that RE can lower the surface energy of molten aluminum and improve the wetting characteristics of molten aluminum on refinement nuclei such as TiAl_3, TiB_2, etc., thus giving full play to the effect of heterogeneous nucleation and impeding the congregating tendency of TiB_2 phase in molten aluminum, at the same time, REs gathering in front of solid/liquid interface are also easy to cause composition supercooling in molten aluminum, thus impeding the growth of α-Al grain and promoting α-Al nucleation on refinement nuclei, in addition, REs have also definitive behavior of purification, or grain refinement, or modification, especially their effect of purification can improve the metallurgical quality of AlTiBRE master alloy.