Providing a new perspective for obtaining high-quality metal coatings: fabrication and properties studies of TA2 foil on Q235 steel by explosive welding

In this work, an improved explosive welding technique was introduced to obtaining high-quality metal coatings, where titanium (TA2) foils with different thicknesses of 0.1, 0.2, 0.3, and 0.4 mm were successfully coated on Q235 steel. Systematic investigations of the achieved claddings were conducted using macro- and micro-morphology observations, EDS elemental analyses, mechanical tests (three-point bending and nanoindentation), and electrochemical measurements. It was concluded that the explosive welding technique was an effective way to produce high-quality TA2 coatings. In both morphological analyses and mechanical tests, an excellent bonding quality was confirmed for the cases of TA2 foils with a thickness of greater than 0.1 mm. Meanwhile, the welding window was proved still being practical for predicting the bonding interface characteristics in the explosive welding of the metal foil. The EDS analyses and nanoindentation tests signified inhomogeneous properties of the materials near the bonding interface due to shock-induced work hardening and the formation of molten zone. Eventually, TA2 foil coatings were certified by electrochemical measurement to remarkably enhance the corrosion resistance of the Q235 substrate.