The Ti-48 Al-2 Nb-2 Cr alloy was deposited and repaired by electron beam. The surface formation and microstructure evolution of Ti-Al intermetallic compound electron beam repair layer were investigated. The results show that Ti-48 Al-2 Nb-2 Cr electron beam repair is easy to generate defects such as pores and cracks. The α

2

phase is gradually increased and the γ phase is gradually decreased from the base material to the center of the repair layer. The grains in the central area of the repair layer are untransformed needle-shaped α

2

/γ phases

and the grain boundaries are massive γ

m

phases. The heat-affected zone of near-repair layer presents a dual-state structure which are composed of fine equiaxed γ grains and α

2

/γ lamellar clusters. The heat-affected zone in near-base-material is mainly composed of large-sized equiaxed γ grains and a few fine strips along the crystal like α

2

phase composition. Due to the diversity of grain size and structure

the microhardness of the alloy at each area is different

presenting a trend of gradually decreasing from the weld to the base material. The center hardness of the repair layer can reach up to 590 HV

0.2

and the average hardness is about 520 HV

0.2

and there is no significant difference in hardness at different depths at the same area.