B对亚共晶钛硅合金凝固行为的影响

Effects of Boron on Solidification Behavior of Hypoeutectic Ti-Al Alloy

研究了微量B对亚共晶钛硅合金(Ti-5Si)微观组织的影响,分析了B原子在金属凝固过程中树枝晶形成和共晶反应中的作用。金相组织观察和SEM试验结果表明,亚共晶钛硅合金(Ti-5Si)中添加微量B,可以显著改变微观组织中树枝晶的形貌,减少初生树枝晶含量,提高共晶组织含量。分析认为,这归因于微量B的添加可以提高亚共晶钛硅合金(Ti-5Si)中硅的当量值。

The effects of minor boron on microstructure of hypoeutectic Ti-5Si alloy have been observed by SEM(scanning electron microscope) and OM(optical microscope),and the Boron atom role on the eutectic transformation and the growth of dendrite during solidification process has been investigated.The results show that the minor B addition can remarkably improve the morphology of the dendrite in the microstructure of hypoeutectic Ti-5Si alloy,decreasing the volumetric fraction of primary dendrite and increasing the volumetric fraction of eutectic phase,which is attributed to the minor B addition raising the Si equivalent value in the hypoeutectic Ti-5Si alloy.