B_2O_3替代KBF_4用氟盐法制备Al-Ti-B晶粒细化剂的研究  

Manufacture of Al-Ti-B Grain Refiner by Reaction of Complex Halide Salts with Molten Aluminum in B_2O_3 Alternative KBF_4

作　　者：任峻[1] 陶钦贵[1] 马颖[2] 

机构地区：[1]宜宾学院计算物理重点实验室,四川宜宾644007 [2]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,甘肃兰州730050

出　　处：《稀有金属》2016年第2期188-192,共5页Chinese Journal of Rare Metals

基　　金：四川省教育厅重点项目(12ZA202)资助

摘　　要：晶粒细化是提高铝合金强度和塑性,改善铸件质量的重要途径。目前,铝合金的晶粒细化主要基于Al-Ti-B三元合金体系采用氟盐法制备,通过在熔融铝合金中添加Al-Ti-B细化剂棒使α-Al晶粒细化,从而获得均匀、细小、等轴晶粒组织。然而,该方法的KBF4和K2Ti F6混合卤盐,尤其是KBF4,增加了生产成本,引起更多的氟化物排放和难处理的残渣,且反应过程造成的热量损失很难由熔体自身的放热反应来弥补。因此,寻找一种更经济、更高效的化合物替代KBF4,为制备新型、质优的Al-Ti-B晶粒细化剂提供了方向。实验表明:用B2O3完全替代氟盐法中的KBF4盐,降低了晶粒细化性能,产生大量的残渣,且降低了熔体的流动性,使浇铸过程更加困难;当B2O3与除渣助熔剂预先混合,再与K2Ti F6混合加入到熔体中时,在不考虑添加物损失的情况下,铝熔体的微观组织结构和细化效率均会得到明显的改善;当B2O3和KBF4各添加50%时,钛的回收率和晶粒的细化效率,几乎与单独添加KBF4时一致。由此得出结论:在不损失晶粒细化效率的前提下,可以用B2O3部分替代KBF4,但绝非全部。该方法的优势在于:具有更低的氟化物排放量和颗粒物添加量,在相同质量下,B2O3提供的硼含量达到4倍,价格也更便宜。Grain refinement was one of the means of increasing strength and plasticity of aluminum alloy and improving quality of castings. Currently,the grain refinement of aluminum alloys mainly depended on the Al-Ti-B alloy ternary system,which added Al-TiB grain refiner robs into molten aluminum in the reaction of complex halide salts to refine α-Al and obtain a uniform,fine and equiaxed structure. However,the mixed malts of the method,KBF4 and K2Ti F6,particularly KBF4,greatly increased the cost of production,caused more fluoride emissions and needed troublesome residue treatment process. Besides,it was difficult to compensate the heat loss of the reaction-self from the exothermic reaction of the molten aluminum. Therefore,it was a direction to find a more economical and efficient compound which could replace KBF4 salt for manufacturing high quality Al-Ti-B grain refiner. The experiment showed that KBF4 was completely replaced by B2O3 during the complex halide salts with molten aluminum to prepare Al-Ti-B grain refiner,which could not only reduce the refiner performance and produce a large amount of residue,but also decrease the fluidity of the molten aluminum and lead to more difficulty to the casting process. With premixing B2O3 and deslagging agent and then adding K2 Ti F6to the molten aluminum,the microstructure and refine efficiency of aluminum alloy would be significantly improved without considering the loss of additives. When each of B2O3 and KBF4was added by 50%,the recovery rate of Ti and the grain refiner efficiency of aluminum alloy were almost consistent with the case that only KBF4 was added. Therefore,we concluded that B2O3 could be used to replace KBF4 only partially but not completely on the premise that grain refining efficiency was not taken into consideration. This method could produce lower fluoride emissions and particulates additive. Moreover,B content that provided by B2O3 was nearly 4 times higher,and the additive of this method was cheaper than other additives in the same mass.

关 键 词：铝合金 AL-TI-B 晶粒细化 

分 类 号：TG292[金属学及工艺—铸造] TG146.21[一般工业技术—材料科学与工程]