Structure and Properties of Ti-Al-Ta and Ti-Al-Cr Cladding Layers Fabricated on Titanium

• Main Authors: Daria V. Lazurenko, Mikhail G. Golkovsky, Andreas Stark, Florian Pyczak, Ivan A. Bataev, Alexey A. Ruktuev, Ivan Yu. Petrov, Ilia S. Laptev
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Metals
• Subjects: non-vacuum electron beam cladding; titanium aluminides; ω-phase; oxidation; wear
• Online Access: https://www.mdpi.com/2075-4701/11/7/1139

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 (P<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mover accent="true"><mn>3</mn><mo>¯</mo></mover></semantics></math></inline-formula>m1). 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.