Design of oxygen-doped TiZrHfNbTa refractory high entropy alloys with enhanced strength and ductility

Iroc, L.K.
Tukac, O.U.
Tanrisevdi, B.B.
El-Atwani, O.
Tunes, M.A.
Kalay, Yunus Eren
Aydoğan Güngör, Eda
© 2022Refractory high entropy alloys (RHEAs) are considered promising materials for high-temperature applications due to their thermal stability and high-temperature mechanical properties. However, most RHEAs have high density (>10 g/cm3) and exhibit limited ductility at low temperatures and softening at high temperatures. In this study, we show that oxygen-doping can be used as a new alloy design strategy for tailoring the mechanical behavior of the TiZrHfNbTa alloy: a novel low-density (7.98 g/cm3) ductile RHEA. Even though the material is a single-phase BCC with some oxides at room temperature, secondary BCC and HCP nano-lamellar structures start to form above 600 °C in addition to the nano-twins which are shown to be stable up to 1000 °C. This alloy shows superior strength and compressive ductility due to the nanoengineered microstructure. The present study sheds light on tailoring the strength-ductility balance in RHEAs by controlling the microstructure of novel RHEAs at the nanoscale via oxygen-doping.
Materials and Design


Development and thermal stability of Cr10Mo25Ta25Ti15V25 refractory high entropy alloys
Tukac, O. Umut; Özalp, Ali; Aydoğan Güngör, Eda (2023-01-01)
Refractory high entropy alloys (RHEAs) are promising materials for extreme environment applications, such as high-temperatures (> 1000 degrees C), corrosion and irradiation. In this study, a new CrMoTaTiV RHEA system has been designed using CALPHAD modeling and thermophysical parameter optimization, and produced by vacuum arc melting. Microstructure at room temperature as well as microstructural stability and me-chanical properties at high temperature have been investigated. It has been found that BCC alloy...
Design and development of iron aluminium intermetallic compounds for structural applications at high temperatures
Yıldırım, Mehmet; Akdeniz, Mahmut Vedat; Mekhrabov, Amdulla O.; Department of Metallurgical and Materials Engineering (2014)
Fe-Al based intermetallic compounds are considered as suitable candidates for structural applications at high temperatures due to their outstanding oxidation and corrosion resistance, good intermediate temperature strength, low density, low cost and relatively high melting point. These outstanding physical and mechanical properties are mainly attributed to their long-range ordered superlattices, deviation from stochiometry and ternary alloying additions. However, poor ductility at ambient temperatures signi...
Single wall bamboo shaped carbon nanotube: A molecular dynamics and electronic study
Malcıoğlu, Osman Barış; Erkoc, S (2006-02-01)
Thermal stability and molecular electronic properties of a single walled, bamboo shaped carbon nanotube has been investigated. Molecular dynamics method is applied to investigate thermal stability, and electronic properties are calculated at the Extended Huckel level. Although bamboo shaped carbon nanotubes observed in experimental literature are multi-walled, it is shown that the suggested structural model in this work, which is single-walled, is also both thermodynamically and energetically stable. Bamboo...
Fabrication of SiO2-stacked diamond membranes and their characteristics for microelectromechanical applications
Bayram, Barış (Elsevier BV, 2011-04-01)
Diamond is a promising microelectromechanical systems (MEMS) material due to its high Young's Modulus and very large thermal conductivity. In this work, ultrananocrystalline diamond was stacked between silicon dioxide to form thermally-stable and robust membranes. These SiO2-stacked diamond layers were processed into MEMS-compatible membranes. For comparison, membranes composed of only SiO2 were fabricated as well. The structural characteristics of these membranes are compared and analyzed for membranes of ...
Development and production of ductile TiZrNbHfTa refractory high entropy alloy system for extreme environments
İroç, Lütfi Koray; Aydoğan Güngör, Eda; Kalay, Yunus Eren; Department of Metallurgical and Materials Engineering (2022-1-13)
High entropy alloy (HEA) is a trending material class that was discovered in the early 2000s. By definition, it consists of a single or dual phase by combining 5-13 elements with a 5-35% atomic ratio. They exhibit extraordinary properties, such as structural, mechanical, corrosive and thermal. Moreover, this field gives an opportunity to combine infinite number of elements with infinite compositions. These properties and opportunities make them candidates for various extreme application areas, which will gr...
Citation Formats
L. K. Iroc et al., “Design of oxygen-doped TiZrHfNbTa refractory high entropy alloys with enhanced strength and ductility,” Materials and Design, vol. 223, pp. 0–0, 2022, Accessed: 00, 2022. [Online]. Available: