Structure and properties of ti‐al‐ta and ti‐al‐cr cladding layers fabricated on titanium

Abstract

Being one of the most high‐demand structural materials, titanium has several disadvantages, including low resistance to high‐temperature oxidation and wear. The properties of titanium and its alloys can be improved by applying protective intermetallic coatings. In this study, 2 mm thick Ti‐Al‐Ta and Ti‐Al‐Cr layers were obtained on titanium workpieces by a non‐vacuum electron‐beam cladding. The microstructure and phase compositions of the samples were different for various alloying elements. The Cr‐containing layer consisted of α2, γ, and B2 phases, while the Ta‐containing layer additionally consisted of ω′ phase (P3m1). At the same atomic concentrations of aluminum and an alloying element in both layers, the volume fraction of the B2/ω phase in the Ti‐41Al‐7Ta alloy was significantly lower than in the Ti‐41Al‐7Cr alloy, and the amount of γ phase was higher. The Ti‐41Al‐7Cr layer had the highest wear resistance (2.1 times higher than that of titanium). The maximum oxidation resistance (8 times higher compared to titanium) was observed for the Ti‐41Al‐7Ta layer.