Structure and properties of the Al–Ti–Cu system diffusion coatings

It has been shown that heat treatment at 700 °C for 2 h + 910 °C for 1 h of an explosively welded composite M1 (copper) + VT1‑0 (titanium) + AD1 (aluminum) with layer thicknesses that ensure the occurrence of a “through” diffusion makes it possible to obtain a copper surface coating having a hardness of 4–6.5 GPa. The main structural components of such composite are solid solutions based on titanium cuprides (Ti₃Cu₄, TiCu₂, TiCu₄) and eutectics TiCu₂+TiCu₄, while the surface layer consists of a mixture of TiAl₃ + CuTi₂Al₅ phases and a two-phase interlayer CuTi₂Al₅ + Al₄Cu₉. The coating structure is free from crystallization defects. In comparison with binary coatings based on intermetallic compounds βTiCu₄ and TiCu₂, its wear resistance is 1.5 times higher.