Microstructural aspects and bonding characteristics of the explosive welded Ti/Ti, Ti/steel and Ti/Ni clads were investigated mainly by TEM microscopy. It was found that the bonding interface was composed of layers of metastable phases such as amorphous phases, icosahedral quasicrystal and intermetallic compounds. These metastable phases are formed as a trace of melting followed by subsequent rapid solidification of thin layers of about 200 nm in thickness along the contact surface of both the component materials. It is concluded that the very thin melting layer is responsible for the bonding of explosively welded Ti base clads and especially amorphous phase formed in the bonding interface keeps high bonding strength.