硼元素对TiAl基合金凝固组织的影响

Effect of Boron on Solidification Structure of TiAl-based Alloy

实验采用真空水冷铜坩埚非自耗真空钨极电弧熔炼炉制备Ti-45Al-xB合金,对比研究了B元素对TiAl基合金凝固组织的影响.结果表明硼元素对TiAl基合金凝固组织具有细化作用,硼含量在0到0.6%范围内时,随着硼含量的增加,合金凝固组织细化程度增加,而与Ti45Al0.6B合金相比,Ti45Al0.8B合金的凝固组织出现粗化现象;相较于二元TiAl合金,硼的添加使合金的片层间距减小;但硼含量为0.4%～0.8%时,随着硼含量的增加,片层间距缓慢增加.硼含量在0～0.8%时,硼元素对Ti45Al合金的作用机理主要包括TiB2对固相生长的阻碍作用以及TiB2的辅助形核作用.

In this experiment,Ti-45Al-xB alloy was prepared by vacuum water-cooled copper crucible non-consumable vacuum tungsten arc melting furnace The results show that boron can refine the solidification structure of TiAl-based alloy.When the boron content is in the range of 0 to 0.6%,the degree of refinement increases with the increase of boron content.However,compared with the Ti45Al0.6 Balloy,the microstructure of Ti45Al0.8B alloy became coarse;compared with the binary TiAl alloy;the addition of boron reduces the interlamellar spacing of the alloy;when the boron content is 0.4%-0.8%,the interlamellar spacing increases slowly with the increase of boron content.When boron content is 0-0.8%,the interaction mechanism of boron on Ti45Al alloy mainly includes TiB2 on the solid-phase growth inhibition and TiB2 assisted nucleation.