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用原位自生法制备了Ti 5 3Al xB合金 ,并用X射线衍射仪、扫描电镜对合金的相组成和微观组织进行了研究 .结果表明 :该合金主要由TiAl和TiB2 两相组成 ;初生TiB2 呈六面棱柱状 ,在TiAlB合金凝固过程中 ,Al原子富集在初生TiB2固 液界面前沿 ,导致固 液界面上B原子过饱和度不均匀性增加 ,使固 液界面变得不稳定 ,从而在TiB2 ( 0 0 0 1 )面上产生凸台或柱棒状分枝 ;分枝的各晶面取向与母体的取向一致 ,在初生TiB2 ( 0 0 0 1 )面的凸台状或柱棒状分枝上能观察到清晰的台阶
Ti 5 3Al xB alloy was prepared by in-situ method and the phase composition and microstructure of the alloy were studied by X-ray diffraction and scanning electron microscopy.The results show that the alloy mainly consists of two phases of TiAl and TiB2, the primary TiB2 In the solidification process of TiAlB alloy, Al atoms are enriched in the front of the primary TiB2 solid-liquid interface, resulting in the increase of the non-uniformity of supersaturation of the B atom in the solid-liquid interface, which makes the solid-liquid interface unstable. TiB2 (0 0 0 1) surface generated bosses or rod-shaped branches; the orientation of each crystal face of the branches consistent with the parental orientation, in the primary TiB2 (0 0 0 1) Can observe a clear level