Physico-chemical nanomaterials science

Study of the role of alloying elements Cr, Ni, Fe, and Al in the improvement of high-temperature (700–800 °C) fracture toughness of Ti-based composites
Vasyliv B.D.1, Kulyk V.V.2, Duriagina Z.A.2,3, Lyutyy P.Ya.2, Kovbasiuk T.M.2, Vavrukh V.I.2, Trostyanchyn A.M.2, Vira V.V.4
1 Department of Hydrogen Technologies and Alternative Energy Materials, Karpenko Physico-Mechanical Institute of the NAS of Ukraine, 5 Naukova str., Lviv 79060, Ukraine.
E-mail: mechengin1111@gmail.com
2 Department of Materials Science and Engineering, Lviv Polytechnic National University, 12 S.Bandera str., Lviv 79000, Ukraine.
3 Department of Materials Engineering, The John Paul II Catholic University of Lublin, 14 Racławickie Al., Lublin 20-950, Poland.
4 Department of Strength of Materials and Structural Mechanics, Lviv Polytechnic National University, 12 S.Bandera str., Lviv 79000, Ukraine.

Advanced Ti-based composites are being used for manufacturing components of state-of-the-art power equipment as well as aircraft and rocket engines owing to their high strength-to-weight ratio and comparatively high fracture toughness in a temperature range of 20 °C to 650 °C. These materials have an advantage over conventional titanium alloys, an operating temperature of which is limited by 350–550 °C. This work is aimed at studying the role of alloying elements Cr, Ni, Fe, and Al in the improvement of high-temperature (700–800 °C) fracture toughness of Ti-based composites.
Ti–Al–X composites (X=Cr and/or Ni and/or Fe) were manufactured with electron arc smelting. The contents of alloying elements marked with X varied in a range of 0.2–41 wt%. Single-edge notch beam fracture toughness tests of specimen series were carried out in a temperature range of 20 °C to 800 °C. The microstructure and phase composition in relation to fracture toughness data and failure micromechanisms of the composites were analysed. The role of alloying elements Cr, Ni, Fe, and Al in the improvement of high-temperature fracture toughness of Ti-based composites was substantiated. It was found that both Ti–Al–Cr and Ti–Al–Ni composites of the optimal phase composition are promising in terms of fracture toughness for high-temperature (700–800 °C) applications.