Enhanced TiAl/Ti3SiC2 diffusion bonding by introducing amorphous intergranular films in Ti3SiC2 through Al doping

The Al-enriched amorphous intergranular films were firstly found and introduced in Ti3SiC2 substrates through Al doping, for enhancing the TiAl/Ti3SiC2 diffusion bonding. The existence of the Al-enriched amorphous intergranular films changed the main diffusion element from Si in the undoped TiAl/Ti3SiC2 joint to Al in the Al-doped joints. The build-ups of the interfacial compounds were γ+α2/γ/Ti5Si3/Ti3SiC2 in the undoped TiAl/Ti3SiC2 joint and were γ+α2/γ/TiAl2/TiAl3+Ti5Si3+Ti5Si4/Ti3SiC2 in the Al-doped joints. The formation of the brittle Ti5Si3 layer was inhibited through Al doping, which enhanced the shear strength of the joint.