TY - JOUR

T1 - Design of oxygen-doped TiZrHfNbTa refractory high entropy alloys with enhanced strength and ductility

AU - Iroc, L. K.

AU - Tukac, O. U.

AU - Tanrisevdi, B. B.

AU - El-Atwani, Osman

AU - Tunes, Matheus

AU - Kalay, Y. E.

AU - Aydogan, E.

N1 - Funding Information: This work was partly supported by the Scientific and Technological Research Council of Turkey under the TUBITAK-2232 program project number 118C239. Authors would like to acknowledge S. Ozturk for the help on TEM, and Stuart Maloy for fruitful discussions. MAT would like to thank the support from the Laboratory Directed Research and Development (LDRD) program of the Los Alamos National Laboratory under project number 20200689PRD2. OEA acknowledges support from the LDRD’s early career program number 20210626ECR and DOE-FES program with code AT2030110. Funding Information: This work was partly supported by the Scientific and Technological Research Council of Turkey under the TUBITAK-2232 program project number 118C239. Authors would like to acknowledge S. Ozturk for the help on TEM, and Stuart Maloy for fruitful discussions. MAT would like to thank the support from the Laboratory Directed Research and Development (LDRD) program of the Los Alamos National Laboratory under project number 20200689PRD2. OEA acknowledges support from the LDRD's early career program number 20210626ECR and DOE-FES program with code AT2030110. Scientific and Technological Research Council of Turkey: grant TUBITAK-2232 program project number 118C239. Laboratory Directed Research and Development (LDRD): grants 20200689PRD2 and 20210626ECR. U.S. Department of Energy: grant AT2030110. All data are available in the main text or the supplementary materials. Publisher Copyright: © 2022

PY - 2022/11

Y1 - 2022/11

N2 - Refractory 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.

AB - Refractory 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.

KW - CALPHAD

KW - In-situ TEM

KW - Nano-lamellar structures

KW - Nanotwins

KW - Refractory High Entropy Alloys (RHEAs)

UR - http://www.scopus.com/inward/record.url?scp=85139850041&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2022.111239

DO - 10.1016/j.matdes.2022.111239

M3 - Article

AN - SCOPUS:85139850041

VL - 223.2022

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

IS - November

M1 - 111239

ER -