AlTiBRE中间合金中各元素含量优化及RE作用分析

Optimization of Elements Proportion and Roles of RE in AlTiBRE Master Alloy

采用氟盐法制备工艺,并用正交试验法对新型细化剂AlTiBRE中间合金中各元素的比例(含量)进行优化试验,同时采用OM、SEM、EDAX等进行细化相粒子存在形态和成分分析。结果表明,各元素含量对该合金细化相粒子存在形态有明显影响,其中Ti含量影响最为显著;由5%Ti、1%B、0.5%RE合金元素组成的中间合金细化相粒子分散性最好,其中TiAl3相呈细小块状,均匀弥散分布于铝基体中,可进一步提高该类细化剂细化效果;此外还探讨了RE在该细化剂制备过程中的作用,指出RE主要阻碍TiB2和TiAl3聚集,起到细化TiB2和TiAl3颗粒作用,还可对该合金熔炼过程中起一定净化作用,保证合金熔体冶金质量。

The new refiner - AITiBRE master alloy was prepared by using the technique of fluorid salts, and its element proportion was optimized by means of orthogonal experiment. At the same time, the analyses of microstructure and component of refining phases in the master alloy were studied with help of OM, SEM, EDAX and XRD. The results indicated that the proportion of the elements in AITiBRE master alloy had significant effect on the distribution of refining particles and Ti had the most obvious effect. The distribution form of refining phase particles was improved further when elements component in the master alloy is 5%Ti, 1%B and 0.5% RE. The TiAl3 phase was fine and distributed homogeneously in the molten aluminum, thus improving refinement effect of the refiner further. In addition, the function of RE in the preparation of the refiner was studied. Results showed that RE mainly impeded the accumulation of TiB2 and TiAl3 in molten aluminum and refined the grains of TiB2 and TiAl3. At the same time, RE can purify the master alloy to some extent during the process of melting, thus ensuring the metallurgical quality of molten master alloy.