Study on Microstructure Formation of TiAl Based Micro-Laminates Deposited by EB-PVD

Abstract

TiAl based micro-laminated sheet was deposited by electron beam physical vapor deposition (EB-PVD) with dual-target in this work, and then the microstructure and phase analysis of as-deposited samples were studied by SEM, XRD and TEM. The results show that the difference of melting points between Ti and Al led to the distinctive structure: the Ti-Al layers were mainly constituted of equiaxed grains and Ti layers were constituted of column grains. Because of the deviation of saturated vapor pressure between Ti and Al element, the component showed a gradient change periodically along the normal direction of Ti-Al layers and results in several sub-layers. The Ti layers, Ti-Al layers and interfacial layers were constituted of α phase, γ+α2 phase and α2 phase respectively.